Accurately assessing for a specific Depressive Disorder diagnosis requires an expenditure of time that is deemed unreasonable for most primary care physicians. For this reason, physicians often use this code as a proxy for a more thorough diagnosis. There is concern that this may lead to a "wastebasket" mindset for certain disorders. In addition reimbursement through Medicare may be lower for certain non specific diagnosis.

Psychosis as a symptom of a psychiatric disorder is first and foremost a diagnosis of exclusion. So a new-onset episode of psychosis "cannot" be considered to be a symptom of a psychiatric disorder until other relevant and known medical causes of psychosis are excluded, or ruled out. Many clinicians improperly perform, or entirely miss this step, introducing avoidable diagnostic error and misdiagnosis.

An initial assessment includes a comprehensive history and physical examination. Although no biological laboratory tests exist which confirm schizoaffective disorder, biological tests should be performed to exclude psychosis associated with or caused by substance use, medications, toxins or poisons, surgical complications, or other medical illnesses. Since non-medical mental health practitioners are not trained to exclude medical causes of psychosis, people experiencing psychosis should be referred to an emergency department or hospital.

Delirium should be ruled out, which can be distinguished by visual hallucinations, acute onset and fluctuating level of consciousness, indicating other underlying factors which includes medical illnesses. Excluding medical illnesses associated with psychosis is performed by using blood tests to measure:

- Thyroid-stimulating hormone to exclude hypo- or hyperthyroidism,

- Basic electrolytes and serum calcium to rule out a metabolic disturbance,

- Full blood count including ESR to rule out a systemic infection or chronic disease, and

- Serology to exclude syphilis or HIV infection.

Other investigations which may be performed include:

- EEG to exclude epilepsy, and an

- MRI or CT scan of the head to exclude brain lesions.

Blood tests are not usually repeated for relapse in people with an established diagnosis of schizoaffective disorder, unless there is a specific "medical" indication. These may include serum BSL if olanzapine has previously been prescribed, thyroid function if lithium has previously been taken to rule out hypothyroidism, liver function tests if chlorpromazine has been prescribed, CPK levels to exclude neuroleptic malignant syndrome, and a urinalysis and serum toxicology screening if substance use is suspected. Assessment and treatment may be done on an outpatient basis; admission to an inpatient facility is considered if there is a risk to self or others.

Because psychosis may be precipitated or exacerbated by common classes of psychiatric medications, such as antidepressants, ADHD stimulant medications, and sleep medications, prescribed medication-induced psychosis should be ruled out, particularly for first-episode psychosis. This is an essential step to reduce diagnostic error and to evaluate potential medication sources of further patient harm. Regarding prescribed medication sources of patient harm, Yale School of Medicine Professor of Psychiatry Malcolm B. Bowers, Jr, MD wrote:

Illicit drugs aren't the only ones that precipitate psychosis or mania—prescribed drugs can too, and in particular, some psychiatric drugs. We investigated this and found that about 1 in 12 psychotic or manic patients in an inpatient psychiatric facility are there due to antidepressant-induced psychosis or mania. That's unfortunate for the field [of psychiatry] and disastrous for some of our patients.

Substance-induced psychosis should also be ruled out. Both substance- and medication-induced psychosis can be excluded to a high level of certainty while the person is psychotic, typically in an emergency department, using both a

- Broad spectrum urine toxicology screening, and a

- Full serum toxicology screening (of the blood).

Some dietary supplements may also induce psychosis or mania, but cannot be ruled out with laboratory tests. So a psychotic person's family, partner, or friends should be asked whether he or she is currently taking any dietary supplements.

Common mistakes made when diagnosing psychotic patients include:

- Not properly excluding delirium,

- Missing a toxic psychosis by not screening for substances "and" medications,

- Not appreciating medical abnormalities (e.g., vital signs),

- Not obtaining a medical history and family history,

- Indiscriminate screening without an organizing framework,

- Not asking family or others about dietary supplements,

- Premature diagnostic closure, and

- Not revisiting or questioning the initial diagnostic impression of primary psychiatric disorder.

Only after these relevant and known causes of psychosis have been ruled out can a psychiatric differential diagnosis be made. A mental health clinician will incorporate family history, observation of a psychotic person's behavior while the person is experiencing active symptoms, to begin a psychiatric differential diagnosis. Diagnosis also includes self-reported experiences, as well as behavioral abnormalities reported by family members, friends, or significant others. Mistakes in this stage include:

- Not screening for dissociative disorders. Dissociative identity disorder and psychotic symptoms in schizoaffective disorder have considerable overlap, yet a different overall treatment approach.

Bipolar disorder is commonly diagnosed during adolescence or early adulthood, but onset can occur throughout the life cycle. The disorder can be difficult to distinguish from unipolar depression and the average delay in diagnosis is 5–10 years after symptoms begin. Diagnosis of bipolar disorder takes several factors into account and considers the self-reported experiences of the symptomatic individual, abnormal behavior reported by family members, friends or co-workers, observable signs of illness as assessed by a clinician, and often a medical work-up to rule-out medical causes. In diagnosis, caregiver-scored rating scales, specifically the mother, has been found to be more accurate than teacher and youth report in predicting identifying youths with bipolar disorder. Assessment is usually done on an outpatient basis; admission to an inpatient facility is considered if there is a risk to oneself or others. The most widely used criteria for diagnosing bipolar disorder are from the American Psychiatric Association's (APA) "Diagnostic and Statistical Manual of Mental Disorders", Fifth Edition (DSM-5) and the World Health Organization's (WHO) "International Statistical Classification of Diseases and Related Health Problems", 10th Edition (ICD-10). The ICD-10 criteria are used more often in clinical settings outside of the U.S. while the DSM criteria are used clinically within the U.S. and are the prevailing criteria used internationally in research studies. The DSM-5, published in 2013, included further and more accurate specifiers compared to its predecessor, the DSM-IV-TR. Semi structured interviews such as the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS) and the Structured Clinical Interview for DSM-IV (SCID) are used for diagnostic confirmation of bipolar disorder.

Several rating scales for the screening and evaluation of bipolar disorder exist, including the Bipolar spectrum diagnostic scale, Mood Disorder Questionnaire, the General Behavior Inventory and the Hypomania Checklist. The use of evaluation scales cannot substitute a full clinical interview but they serve to systematize the recollection of symptoms. On the other hand, instruments for screening bipolar disorder tend to have lower sensitivity.

The past DSM-IV criteria for IED were similar to the current criteria, however verbal aggression was not considered as part of the diagnostic criteria. The DSM-IV diagnosis was characterized by the occurrence of discrete episodes of failure to resist aggressive impulses that result in violent assault or destruction of property. Additionally, the degree of aggressiveness expressed during an episode should be grossly disproportionate to provocation or precipitating psychosocial stressor, and, as previously stated, diagnosis is made when certain other mental disorders have been ruled out, e.g., a head injury, Alzheimer's disease, etc., or due to substance abuse or medication. Diagnosis is made using a psychiatric interview to affective and behavioral symptoms to the criteria listed in the DSM-IV.

The DSM-IV-TR was very specific in its definition of Intermittent Explosive Disorder which was defined, essentially, by exclusion of other conditions. The diagnosis required:

1. several episodes of impulsive behavior that result in serious damage to either persons or property, wherein

2. the degree of the aggressiveness is grossly disproportionate to the circumstances or provocation, and

3. the episodic violence cannot be better accounted for by another mental or physical medical condition.

The most widely used criteria for diagnosing schizoaffective disorder are from the American Psychiatric Association's "Diagnostic and Statistical Manual of Mental Disorders-5".

The DSM-IV schizoaffective disorder definition was plagued by problems of being inconsistently (or unreliably) used on patients; when the diagnosis is made, it doesn't stay with most patients over time; and it has questionable diagnostic validity (that is, it doesn't describe a distinct disorder, nor predict any particular outcome). These problems have been slightly reduced (or "modestly improved") in the DSM-5 according to Carpenter.

When psychotic symptoms are confined to an episode of mania or depression (with or without mixed features), the diagnosis is that of a “psychotic” mood disorder, namely either bipolar disorder or major depression). Only when psychotic states persist in a sustained fashion for two weeks or longer without concurrent affective symptoms is the diagnosis schizoaffective disorder or schizophrenia.

The second cardinal guideline in the DSM-5 diagnosis of schizoaffective disorder is one of timeframe.

These two changes are intended by the DSM-5 workgroup to accomplish two goals:

- Increase the diagnosis' consistency (or reliability) when it is used;

- Significantly decrease the overall use of the schizoaffective disorder diagnosis.

If the schizoaffective diagnosis is used less often, other diagnoses (like psychotic mood disorders and schizophrenia) are likely to be used more often; but this is hypothetical until real-world data arrive. Validity problems with the diagnosis remain and await further work in the fields of psychiatric genetics, neuroimaging, and cognitive science that includes the overlapping fields of cognitive, affective, and social neuroscience, which may change the way schizoaffective disorder is conceptualized and defined in future versions of the DSM and ICD.

Diagnosis of cyclothymia is difficult for a number of reasons. The depressive-dysthymic episode of cyclothymia is also a diagnostic feature of many disorders, including adjustment disorders, personality disorders, psychotic disorders, and other mood disorders. Since depression can be triggered or exacerbated by life events and circumstances, the diagnosing clinician must determine when it is an acceptable response and when it is pathological.

Symptoms described in the hypomanic episode are also commonly associated with ADHD, such as increased energy, distractibility and impulsive or risk-seeking behavior. This is of particular concern in child psychiatry because symptoms, especially hyperactivity, may be counted twice toward both disorders or may inflate the prevalence of ADHD.

While childhood ADHD often presents with hyperactivity, adult ADHD often does not. The unstable lifestyle often found both in people with ADHD and in those with cyclothymia can cause problems for differential diagnosis. Important distinguishing factors include that ADHD is characterized mainly by problems with concentration and memory, while cyclothymia mainly by periods of elevated self-confidence and elation.

Whether subtypes of bipolar disorder, such as cyclothymia truly represent separate disorders or are part of a unique bipolar spectrum is still debated in research. Cyclothymia is typically not described in research studies or diagnosed in clinical settings, making it less recognizable and less understood by professionals. This absence of cyclothymia in research and clinical settings suggests that cyclothymia is either being diagnosed as another mood disorder or as a non-affective psychiatric disorder or not coming to scientific or clinical attention due to a lack of diagnostic clarity or because the nature of cyclothymia is still highly contested. Additionally, the current diagnostic criterion for cyclothymia emphasizes that symptoms are persistent, which suggests that they are enduring traits rather than a psychological state, thus, it has been argued that it should be diagnosed as a personality disorder. Since the symptoms tend to overlap with personality disorders, the validity and distinction between these two diagnostic categories has been debated.

Lastly, the tendency of cyclothymia to be comorbid with other mental disorders makes diagnosis difficult. These issues prevent consensus on the definition of cyclothymia and its relationship with other mental disorders among researchers and clinicians. This lack of consensus on an operational definition and symptom presentation is especially pronounced with children and adolescents because the diagnostic criteria have not been adequately adapted to take into account their developmental level. However, there has been a shift from categorical models of bipolar related disorders toward a dimensional model, which is intended to address some of these issues.

This disorder is common in the relatives of patients with bipolar disorder, and some individuals with cyclothymia eventually develop bipolar disorder themselves. It may persist throughout adult life, cease temporarily or permanently, or develop into more severe mood swings, meeting the criteria for bipolar disorder or recurrent depressive disorder in some cases.

Many psychiatric disorders and some substance use disorders are associated with increased aggression and are frequently comorbid with IED, often making differential diagnosis difficult. Individuals with IED are, on average, four times more likely to develop depressive or anxiety disorders, and three times more likely to develop substance use disorders.

Bipolar disorder has been linked to increased agitation and aggressive behavior in some individuals, but for these individuals aggressiveness is limited to manic and/or depressive episodes, whereas individuals with IED experience aggressive behavior even during periods with a neutral or positive mood. In one clinical study, the two disorders co-occurred 60% of the time. Patients report manic-like symptoms occurring just before outbursts and continuing throughout. According to a study, the average onset age of IED was around five years earlier than the onset age of bipolar disorder, indicating a possible correlation between the two.

Similarly, alcohol and other substance use disorders may exhibit increased aggressiveness, but unless this aggression is experienced outside of periods of acute intoxication and withdrawal, no diagnosis of IED is given. For chronic disorders, such as PTSD, it is important to assess whether the level of aggression met IED criteria prior to the development of another disorder. In antisocial personality disorder, interpersonal aggression is usually instrumental in nature (i.e., motivated by tangible rewards), whereas IED is more of an impulsive, unpremeditated reaction to situational stress.

There are several other mental disorders with symptoms similar to those seen in bipolar disorder. These disorders include schizophrenia, major depressive disorder, attention deficit hyperactivity disorder (ADHD), and certain personality disorders, such as borderline personality disorder.

Although there are no biological tests that are diagnostic of bipolar disorder, blood tests and/or imaging may be carried out to exclude medical illnesses with clinical presentations similar to that of bipolar disorder. Neurologic diseases such as such as multiple sclerosis, complex partial seizures, strokes, brain tumors, Wilson disease, traumatic brain injury, Huntington's disease, and complex migraines can mimic features of bipolar disorder. An EEG may be used to exclude neurological disorders such as epilepsy, and a CT scan or MRI of the head may be used to exclude brain lesions. Additionally, disorders of the endocrine system such as hypothyroidism, hyperthyroidism, and Cushing's disease are in the differential as is the connective tissue disease systemic lupus erythematosus. Infectious causes of mania which may appear similar to bipolar mania include herpes encephalitis, HIV, influenza, or neurosyphilis. Certain vitamin deficiencies such as pellagra (niacin deficiency), Vitamin B12 deficiency, folate deficiency, and Wernicke Korsakoff syndrome (thiamine deficiency) can also lead to mania.

A review of current and recent medications and drug use is considered to rule out these causes; common medications that can cause manic symptoms include antidepressants, prednisone, Parkinson's disease medications, thyroid hormone, stimulants (including cocaine and methamphetamine), and certain antibiotics.

It is possible for this disorder to progress over time. A patient suffering from the disorder can improve the condition with treatments. There are several types of therapies that may improve the condition, but depending on a patient’s experience of the disorder or the cause of the disorder, treatments will vary.

- Psychotherapy including behaviour therapy, Gestalt therapy, Adlerian therapy, psychoanalytic therapy and existential therapy.

- Pharmacotherapy through medications including antidepressants.

Formal diagnosis may be performed by a psychologist, psychiatrist, clinical social worker, or other licensed mental health professional. To be diagnosed with OCD, a person must have obsessions, compulsions, or both, according to the Diagnostic and Statistical Manual of Mental Disorders (DSM). The Quick Reference to the 2000 edition of the DSM states that several features characterize clinically significant obsessions and compulsions. Such obsessions, the DSM says, are recurrent and persistent thoughts, impulses or images that are experienced as intrusive and that cause marked anxiety or distress. These thoughts, impulses or images are of a degree or type that lies outside the normal range of worries about conventional problems. A person may attempt to ignore or suppress such obsessions, or to neutralize them with some other thought or action, and will tend to recognize the obsessions as idiosyncratic or irrational.

Compulsions become clinically significant when a person feels driven to perform them in response to an obsession, or according to rules that must be applied rigidly, and when the person consequently feels or causes significant distress. Therefore, while many people who do not suffer from OCD may perform actions often associated with OCD (such as ordering items in a pantry by height), the distinction with clinically significant OCD lies in the fact that the person who suffers from OCD "must" perform these actions, otherwise they will experience significant psychological distress. These behaviors or mental acts are aimed at preventing or reducing distress or preventing some dreaded event or situation; however, these activities are not logically or practically connected to the issue, or they are excessive. In addition, at some point during the course of the disorder, the individual must realize that their obsessions or compulsions are unreasonable or excessive.

Moreover, the obsessions or compulsions must be time-consuming (taking up more than one hour per day) or cause impairment in social, occupational or scholastic functioning. It is helpful to quantify the severity of symptoms and impairment before and during treatment for OCD. In addition to the peron's estimate of the time spent each day harboring obsessive-compulsive thoughts or behaviors, concrete tools can be used to gauge the people’s condition. This may be done with rating scales, such as the Yale–Brown Obsessive Compulsive Scale (Y-BOCS). With measurements like these, psychiatric consultation can be more appropriately determined because it has been standardized.

OCD is sometimes placed in a group of disorders called the obsessive–compulsive spectrum.

Diagnosis of borderline personality disorder is based on a clinical assessment by a mental health professional. The best method is to present the criteria of the disorder to a person and to ask them if they feel that these characteristics accurately describe them. Actively involving people with BPD in determining their diagnosis can help them become more willing to accept it. Although some clinicians prefer not to tell people with BPD what their diagnosis is, either from concern about the stigma attached to this condition or because BPD used to be considered untreatable, it is usually helpful for the person with BPD to know their diagnosis. This helps them know that others have had similar experiences and can point them toward effective treatments.

In general, the psychological evaluation includes asking the patient about the beginning and severity of symptoms, as well as other questions about how symptoms impact the patient's quality of life. Issues of particular note are suicidal ideations, experiences with self-harm, and thoughts about harming others. Diagnosis is based both on the person's report of their symptoms and on the clinician's own observations. Additional tests for BPD can include a physical exam and laboratory tests to rule out other possible triggers for symptoms, such as thyroid conditions or substance abuse. The ICD-10 manual refers to the disorder as "emotionally unstable personality disorder" and has similar diagnostic criteria. In the DSM-5, the name of the disorder remains the same as in the previous editions.

The following are the revised criteria for a diagnosis of cyclothymic disorder (DSM-IV-TR 301.13) from the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-IV-TR):

- A. For at least 2 years (1 year in children and adolescents), the presence of numerous periods with hypomanic symptoms and numerous periods with depressive symptoms that do not meet criteria for a Major Depressive Episode

- B. During the above period, the person has not been without the symptoms in A for more than 2 months in the 2-year period

- C. No Major Depressive Episode, Manic Episode, or Mixed Episode has been present during the first 2 years of the disturbance.

- D. The symptoms in Criterion A are not better accounted for by Schizoaffective Disorder and are not superimposed on Schizophrenia, Schizophreniform Disorder, Delusional Disorder, or Psychotic Disorder Not Otherwise Specified.

- E. The symptoms are not due to the direct physiological effects of a substance (e.g. drug of abuse, a medication) or a general medical condition (e.g., hyperthyroidism).

- F. The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

The DSM-IV-TR notes that the mood disturbance must be not severe enough to constitute a full-fledged manic or major depressive episode. The diagnosis requires that there be periods of both hypomania and depression and that periods of normal mood not last longer than 2 months.

The DSM-IV-TR also notes that Cyclothymia and borderline personality disorder share similar features and that individuals can be diagnosed with both BPD and Cyclothymia depending on the symptoms they present.

Healthcare providers may screen patients for depression using a screening tool, such as the Patient Healthcare Questionnaire-2 (PHQ-2).

To diagnose a major depressive episode, a trained healthcare provider must make sure that:

- The symptoms do not meet the criteria for a mixed episode.

- The symptoms must cause considerable distress or impair functioning at work, in social settings or in other important areas in order to qualify as an episode.

- The symptoms are not due to the direct physiological effects of a substance (e.g., abuse of a drug or medication) or a general medical condition (e.g., hypothyroidism).

- Other than in the case of severe symptoms (severely impaired functioning, severe preoccupation with worthlessness, ideas of suicide, delusions or hallucinations or psychomotor retardation).

According to the American Psychiatric Association DSM-IV criteria, Seasonal Affective Disorder is not regarded as a separate disorder. It is called a "course specifier" and may be applied as an added description to the pattern of major depressive episodes in patients with major depressive disorder or patients with bipolar disorder.

The "Seasonal Pattern Specifier" must meet four criteria: depressive episodes at a particular time of the year; remissions or mania/hypomania at a characteristic time of year; these patterns must have lasted two years with no nonseasonal major depressive episodes during that same period; and these seasonal depressive episodes outnumber other depressive episodes throughout the patient's lifetime. The Mayo Clinic describes three types of SAD, each with its own set of symptoms.

Questionnaires and checklists such as the Beck Depression Inventory or the Children's Depression Inventory can be used by a mental health provider to help detect, and assess the severity of depression. The Seasonal Pattern Assessment Questionnaire can be used to screen for seasonal affective disorder. Semi structured interviews such as the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS) and the Structured Clinical Interview for DSM-IV (SCID) are used for diagnostic confirmation of depression.

More than two-thirds of people diagnosed with BPD also meet the criteria for another Axis II personality disorder at some point in their lives. (In a 2008 study, the rate was 73.9 percent.) Cluster A disorders, which include paranoid, schizoid, and schizotypal, are the most common, with a prevalence of 50.4 percent in people with BPD.

The second most common is another Cluster B disorder, which includes antisocial, histrionic, and narcissistic. These have an overall prevalence of 49.2 percent in people with BPD, with narcissistic being the most common, at 38.9 percent; antisocial the second most common, at 13.7 percent; and histrionic the least common, at 10.3 percent. The least common are Cluster C disorders, which include avoidant, dependent, and obsessive-compulsive, and have a prevalence of 29.9 percent in people with BPD. The percentages for specific comorbid Axis II disorders can be found in the adjacent table.

According to a substantial amount of epidemiology studies conducted, women are twice as likely to develop certain mood disorders, such as major depression. Although there is an equal number of men and women diagnosed with bipolar II disorder, women have a slightly higher frequency of the disorder.

In 2011, mood disorders were the most common reason for hospitalization among children aged 1–17 years in the United States, with approximately 112,000 stays. Mood disorders were top principal diagnosis for Medicaid super-utilizers in the United States in 2012. Further, a study of 18 States found that mood disorders accounted for the highest number of hospital readmissions among Medicaid patients and the uninsured, with 41,600 Medicaid patients and 12,200 uninsured patients being readmitted within 30 days of their index stay—a readmission rate of 19.8 per 100 admissions and 12.7 per 100 admissions, respectively. In 2012, mood and other behavioral health disorders were the most common diagnoses for Medicaid-covered and uninsured hospital stays in the United States (6.1% of Medicaid stays and 5.2% of uninsured stays).

A study conducted in 1988 to 1994 amongst young American adults involved a selection of demographic and health characteristics. A population-based sample of 8,602 men and women ages 17–39 years participated. Lifetime prevalence were estimated based on six mood measures:

1. major depressive episode (MDE) 8.6%,

2. major depressive disorder with severity (MDE-s) 7.7%,

3. dysthymia 6.2%,

4. MDE-s with dysthymia 3.4%,

5. any bipolar disorder 1.6%, and

6. any mood disorder 11.5%.

The naturally occurring sugar inositol has been suggested as a treatment for OCD.

Nutrition deficiencies may also contribute to OCD and other mental disorders. Vitamin and mineral supplements may aid in such disorders and provide nutrients necessary for proper mental functioning.

μ-Opioids, such as hydrocodone and tramadol, may improve OCD symptoms. Administration of opiate treatment may be contraindicated in individuals concurrently taking CYP2D6 inhibitors such as fluoxetine and paroxetine.

Much current research is devoted to the therapeutic potential of the agents that affect the release of the neurotransmitter glutamate or the binding to its receptors. These include riluzole, memantine, gabapentin, N-acetylcysteine, topiramate and lamotrigine.

Treatments for classic (winter-based) seasonal affective disorder include light therapy, medication, ionized-air administration, cognitive-behavioral therapy and carefully timed supplementation of the hormone melatonin.

Photoperiod-related alterations of the duration of melatonin secretion may affect the seasonal mood cycles of SAD. This suggests that light therapy may be an effective treatment for SAD. Light therapy uses a lightbox which emits far more lumens than a customary incandescent lamp. Bright white "full spectrum" light at 10,000 lux, blue light at a wavelength of 480 nm at 2,500 lux or green (actually cyan or blue-green) light at a wavelength of 500 nm at 350 lux are used, with the first-mentioned historically preferred.

Bright light therapy is effective with the patient sitting a prescribed distance, commonly 30–60 cm, in front of the box with her/his eyes open but not staring at the light source for 30–60 minutes. A study published in May 2010 suggests that the blue light often used for SAD treatment should perhaps be replaced by green or white illumination. Discovering the best schedule is essential. One study has shown that up to 69% of patients find lightbox treatment inconvenient and as many as 19% stop use because of this.

Dawn simulation has also proven to be effective; in some studies, there is an 83% better response when compared to other bright light therapy. When compared in a study to negative air ionization, bright light was shown to be 57% effective vs. dawn simulation 50%. Patients using light therapy can experience improvement during the first week, but increased results are evident when continued throughout several weeks. Most studies have found it effective without use year round but rather as a seasonal treatment lasting for several weeks until frequent light exposure is naturally obtained.

Light therapy can also consist of exposure to sunlight, either by spending more time outside or using a computer-controlled heliostat to reflect sunlight into the windows of a home or office. Although light therapy is the leading treatment for seasonal affective disorder, prolonged direct sunlight or artificial lights that don't block the ultraviolet range should be avoided due to the threat of skin cancer.

SSRI (selective serotonin reuptake inhibitor) antidepressants have proven effective in treating SAD. Effective antidepressants are fluoxetine, sertraline, or paroxetine. Both fluoxetine and light therapy are 67% effective in treating SAD according to direct head-to-head trials conducted during the 2006 Can-SAD study. Subjects using the light therapy protocol showed earlier clinical improvement, generally within one week of beginning the clinical treatment. Bupropion extended-release has been shown to prevent SAD for one in eight people, but has not been compared directly to other preventive options in trials.

Negative air ionization, which involves releasing charged particles into the sleep environment, has been found effective with a 47.9% improvement if the negative ions are in sufficient density (quantity).

Depending upon the patient, one treatment (e.g., lightbox) may be used in conjunction with another (e.g., medication).

Modafinil may be an effective and well-tolerated treatment in patients with seasonal affective disorder/winter depression.

Another explanation is that vitamin D levels are too low when people do not get enough Ultraviolet-B on their skin. An alternative to using bright lights is to take vitamin D supplements. However, studies did not show a link between vitamin D levels and depressive symptoms in elderly Chinese nor among elderly British women.

Physical exercise has shown to be an effective form of depression therapy, particularly when in addition to another form of treatment for SAD. One particular study noted marked effectiveness for treatment of depressive symptoms when combining regular exercise with bright light therapy. Patients exposed to exercise which had been added to their treatments in 20 minutes intervals on the aerobic bike during the day along with the same amount of time underneath the UV light were seen to make quick recovery.

Authoritative diagnostic criteria for PMDD are provided by a number of expert medical guides, notably the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5). The "Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)," established seven criteria (A through G) for the diagnosis of PMDD.

Diagnostic Criteria:

Criterion A is that in most menstrual cycles during the past year, at least 5 of the following 11 symptoms (including at least 1 of the first 4 listed) must be present in the final week before the onset of menses, start to improve within a few days after the onset of menses, and become minimal or absent in the week postmenses.

1. Marked lability (e.g., mood swings)

2. Marked irritability or anger

3. Markedly depressed mood

4. Marked anxiety and tension

5. Decreased interest in usual activities

6. Difficulty in concentration

7. Lethargy and marked lack of energy

8. Marked change in appetite (e.g., overeating or specific food cravings)

9. Hypersomnia or insomnia

10. Feeling overwhelmed or out of control

11. Physical symptoms (e.g., breast tenderness or swelling, joint or muscle pain, a sensation of ‘bloating’ and weight gain)

Criterion B one (or more) of the following symptoms must be present:

1. Marked affective lability (e.g., mood swings; feeling suddenly sad or tearful, or increased sensitivity to rejection).

2. Marked irritability or anger or increased interpersonal conflicts.

3. Marked depressed mood, feelings of hopelessness, or self-deprecating thoughts.

4. Marked anxiety, tension, and/or feelings of being keyed up or on edge.

Criterion C one (or more) of the following symptoms must be present additionally, to reach a total of "five" symptoms when combined with symptoms from Criterion B above.

1. Decreased interest in usual activities (e.g., work, school, friends, hobbies).

2. Subjective difficulty in concentration.

3. Lethargy, easy fatigability, or marked lack of energy.

4. Marked change in appetite; overeating; or specific food cravings.

5. Hypersomnia or insomnia.

6. A sense of being overwhelmed or out of control.

7. Physical symptoms such as breast tenderness or swelling, joint or muscle pain, a sensation of "bloating," or weight gain.

Note: The symptoms in Criteria A-C must have been met for most menstrual cycles that occurred in the preceding year.

Criterion D The symptoms are associated with clinically significant distress or interference with work, school, usual social activities, or relationships with others (e.g., avoidance of social activities; decreased productivity and efficiency at work, school, or home).

Criterion E The disturbance is not merely an exacerbation of the symptoms of another disorder, such as major depressive disorder, panic disorder, persistent depressive disorder (dysthymia), or a personality disorder (although it may co-occur with any of these disorders).

Criterion F Criterion A should be confirmed by prospective daily ratings during at least two symptomatic cycles. (Note: The diagnosis may be made provisionally prior to this confirmation.)

Criterion G The symptoms are not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication, other treatment) or another medical condition (e.g., hyperthyroidism).

According to the DSM-5, a diagnosis of PMDD requires the presence of at least five of these symptoms with one of the symptoms being number 1-4 (marked lability, irritability, depressed mood, anxiety and tension). These symptoms should occur during the week before menses and remit after initiation of menses. In order to meet criteria for the diagnosis, the symptoms should be charted prospectively for two consecutive ovulation cycles in order to confirm temporal and cyclical nature of symptoms. The symptoms should also be severe enough to affect normal work, school, or social activities or relationships with others.

Other organizations that have published diagnostic criteria for PMDD include the American College of Obstetricians and Gynecologists, the Royal College of Obstetricians and Gynecologists, and the International Society for the Study of Premenstrual Disorders (ISPMD). The ISPMD was a consensus group established by an international multidisciplinary group of experts. The group's diagnostic criteria for PMDD focuses on the cyclic nature of the symptom occurring during the luteal phase of the menstrual cycle, symptoms being absent after menstruation and before ovulation and causing significant impairment. The ISPMD diagnostic criteria for PMDD do not specify symptom characteristics or number of symptoms.

Diagnostic criteria for PMDD are also provided by the 2016 World Health Organization's International Classification of Diseases (ICD-10-CM):

Premenstrual tension syndrome

A more severe and disabling form of premenstrual syndrome in which mood symptoms are the primary characteristic.

A term used to describe the psychological aspects of premenstrual syndrome, such as the "indescribable tension", depression, hostility, and increased seizure activity in people with seizure disorder.

Applicable To

Premenstrual dysphoric disorder ...

Thus today many well-recognized health organizations in many parts of the world provide guides for the diagnosis of PMDD. As a historical footnote, early drafts of the ICD failed to recognize PMDD as a separate condition. In 2003, before the current ICD 10 guidelines, the Committee for Proprietary Medicinal Products required the manufacturer of Prozac (fluoxetine) to remove PMDD from the list of indications for fluoxetine sold in Europe. Reflecting an earlier approach by the ICD, the committee found in 2003 that PMDD was not a well-established disease entity across Europe, and noted "considerable concern that [people] with less severe pre-menstrual symptoms might erroneously receive a diagnosis of PMDD resulting in widespread inappropriate short and long-term use of fluoxetine."

In Australia, PMDD is recognized by the Therapeutic Goods Administration. However, SSRIs are not reimbursed for PMDD under the Pharmaceutical Benefits Scheme.

The DSM-5, released in May 2013, separates the mood disorder chapter from the DSM-TR-IV into two sections: Depressive and Related Disorders and Bipolar and Related Disorders. Bipolar Disorders falls in between Depressive Disorders and Schizophrenia Spectrum and Related Disorders “in recognition of their place as a bridge between the two diagnostic classes in terms of symptomatology, family history and genetics” (Ref. 1, p 123). Bipolar Disorders underwent a few changes in the DSM-5, most notably the addition of more specific symptomology related to hypomanic and mixed manic states. Depressive Disorders underwent the most changes, the addition of three new disorders: disruptive mood dysregulation disorder, persistent depressive disorder (previously dysthymia), and premenstrual dysphoric disorder (previously in Appendix B, the section for disorders needing further research). Disruptive mood dysregulation disorder is meant as a diagnosis for children and adolescents who would normally be diagnosed with bipolar disorder as a way to limit the bipolar diagnosis in this age cohort. Major depressive disorder (MDD) also underwent a notable change, in that the bereavement clause has been removed. Those previously exempt from a diagnosis of MDD due to bereavement are now candidates for the MDD diagnosis.

Affective disorders in patients with MD can only be detected by means of a clinician-administered diagnostic interview. Organic exclusion rules and other criteria are used in making the diagnosis of MD.

The affective spectrum is a spectrum of affective disorders (mood disorders). It is a grouping of related psychiatric and medical disorders which may accompany bipolar, unipolar, and schizoaffective disorders at statistically higher rates than would normally be expected. These disorders are identified by a common positive response to the same types of pharmacologic treatments. They also aggregate strongly in families and may therefore share common heritable underlying physiologic anomalies.

Affective spectrum disorders include:

- Attention deficit hyperactivity disorder

- Bipolar disorder

- Body dysmorphic disorder

- Bulimia nervosa and other eating disorders

- Cataplexy

- Dysthymia

- Generalized anxiety disorder

- Hypersexuality

- Irritable bowel syndrome

- Impulse-control disorders

- Kleptomania

- Migraine

- Major depressive disorder

- Obsessive-compulsive disorder

- Oppositional defiant disorder

- Panic disorder

- Posttraumatic stress disorder

- Premenstrual dysphoric disorder

- Social anxiety disorder

- Fibromyalgia

The following may also be part of the spectrum accompanying affective disorders.

- Chronic pain

- Intermittent explosive disorder

- Pathological gambling

- Personality disorder

- Pyromania

- Substance abuse and addiction (includes alcoholism)

- Trichotillomania

Also, there are now studies linking heart disease.

Many of the terms above overlap. The American Psychiatric Association's definitions of these terms can be found in the "Diagnostic and Statistical Manual of Mental Disorders" (DSM).

The person may have repeated thoughts about death (other than the fear of dying) or suicide (with or without a plan), or may have made a suicide attempt. The frequency and intensity of thoughts about suicide can range from believing that friends and family would be better off if one were dead, to frequent thoughts about committing suicide (generally related to wishing to stop the emotional pain), to detailed plans about how the suicide would be carried out. Those who are more severely suicidal may have made specific plans and decided upon a day and location for the suicide attempt.

20-30% of people who menstruate experience symptoms severe enough to meet PMS criteria and 3-8% of people who are of reproductive age meet the PMDD criteria.

Bipolar depression, anxiety disorders, and other Axis I disorders are more common in people with PMDD than in the general population. In people with PMDD, there is a 50-78% lifetime incidence of various psychiatric disorders such as generalized anxiety disorder, seasonal affective disorder and major depressive disorder.

The symptoms in which coincide with mood disorders, such as major depressive disorder or bipolar disorder, may worsen during the premenstrual period and thus may mimic PMDD. This phenomenon is known as premenstrual exacerbation (PME) and refers to the worsening of mood disorder symptoms during the premenstrual phase. An estimated 40% of people who seek treatment for PMDD are found to not have PMDD, but rather a PME of an underlying mood disorder.

Medical personnel can avoid misdiagnosis by having people seeking treatment for PMDD use a daily charting method to record their symptoms. Daily charting helps distinguish when mood disturbances are experienced and allows PMDD to be distinguished from other mood disorders. With PMDD, mood symptoms are present only during the luteal phase, or last two weeks, of the menstrual cycle. While PMDD mood symptoms are of a cyclical nature, other mood disorders are variable or constant over time. Although the medical community lacks a consensus on the most efficient instrument by which to confirm a PMDD diagnosis, several well-validated scales for recording premenstrual symptoms include the Calendar of Premenstrual Experiences (COPE), Daily Record of Severity of Problems (DRSP), and Prospective Record of the Severity of Menstruation (PRISM).

PMDD mood symptoms are only present in people who are menstruating. Thus, symptoms do not occur during pregnancy and after menopause. Other mood disorders typically persist across all reproductive life events and are independent of a person's menstrual cycle or lack thereof.

In addition to AXIS I disorders, several other medical illnesses such as chronic fatigue syndrome, fibromyalgia, irritable bowel syndrome and migraine disorder may present symptoms similar or identical to those of PMDD. Clinicians must distinguish between PMDD and other medical and/or psychiatric conditions.