Borderline personality disorder may be characterized by the following signs and symptoms:

- Markedly disturbed sense of identity

- Frantic efforts to avoid real or imagined abandonment and extreme reactions to such

- Splitting ("black-and-white" thinking)

- Impulsivity and impulsive or dangerous behaviours

- Intense or uncontrollable emotional reactions that often seem disproportionate to the event or situation

- Unstable and chaotic interpersonal relationships

- Self-damaging behavior

- Distorted self-image

- Dissociation

- Frequently accompanied by depression, anxiety, anger, substance abuse, or rage

The most distinguishing symptoms of BPD are marked sensitivity to rejection or criticism, and intense fear of possible abandonment. Overall, the features of BPD include unusually intense sensitivity in relationships with others, difficulty regulating emotions, and impulsivity. Other symptoms may include feeling unsure of one's personal identity, morals, and values; having paranoid thoughts when feeling stressed; dissociation and depersonalization; and, in moderate to severe cases, stress-induced breaks with reality or psychotic episodes.

People with BPD may feel emotions with greater ease, depth and for a longer time than others do. A core characteristic of BPD is affective instability, which generally manifests as unusually intense emotional responses to environmental triggers, with a slower return to a baseline emotional state. People with BPD often engage in idealization and devaluation of others, alternating between high positive regard for people and great disappointment in them. In Marsha Linehan's view, the sensitivity, intensity, and duration with which people with BPD feel emotions have both positive and negative effects. People with BPD are often exceptionally enthusiastic, idealistic, joyful, and loving. However, they may feel overwhelmed by negative emotions ("anxiety, depression, guilt/shame, worry, anger, etc."), experiencing intense grief instead of sadness, shame and humiliation instead of mild embarrassment, rage instead of annoyance, and panic instead of nervousness.

People with BPD are also especially sensitive to feelings of rejection, criticism, isolation, and perceived failure. Before learning other coping mechanisms, their efforts to manage or escape from their very negative emotions may lead to emotional isolation, self-injury or suicidal behavior. They are often aware of the intensity of their negative emotional reactions and, since they cannot regulate them, they shut them down entirely. This can be harmful to people with BPD, since negative emotions alert people to the presence of a problematic situation and move them to address it which the person with BPD would normally be aware of only to cause further distress. People with BPD may feel emotional relief after cutting themselves.

While people with BPD feel euphoria (ephemeral or occasional intense joy), they are especially prone to dysphoria (a profound state of unease or dissatisfaction), depression, and/or feelings of mental and emotional distress. Zanarini et al. recognized four categories of dysphoria that are typical of this condition: extreme emotions, destructiveness or self-destructiveness, feeling fragmented or lacking identity, and feelings of victimization. Within these categories, a BPD diagnosis is strongly associated with a combination of three specific states: feeling betrayed, "feeling like hurting myself", and feeling out of control. Since there is great variety in the types of dysphoria experienced by people with BPD, the amplitude of the distress is a helpful indicator of borderline personality disorder. In addition to intense emotions, people with BPD experience emotional "lability"; or in other words, changeability. Although the term emotional lability suggests rapid changes between depression and elation, the mood swings in people with this condition actually fluctuate more frequently between anger and anxiety and between depression and anxiety.

In cognitive models of social anxiety disorder, those with social phobias experience dread over how they will be presented to others. They may feel overly self-conscious, pay high self-attention after the activity, or have high performance standards for themselves. According to the social psychology theory of self-presentation, a sufferer attempts to create a well-mannered impression towards others but believes he or she is unable to do so. Many times, prior to the potentially anxiety-provoking social situation, sufferers may deliberately review what could go wrong and how to deal with each unexpected case. After the event, they may have the perception that they performed unsatisfactorily. Consequently, they will perceive anything that may have possibly been abnormal as embarrassing. These thoughts may extend for weeks or longer. Cognitive distortions are a hallmark, and are learned about in CBT (cognitive-behavioral therapy). Thoughts are often self-defeating and inaccurate. Those with social phobia tend to interpret neutral or ambiguous conversations with a negative outlook, and many studies suggest that socially anxious individuals remember more negative memories than those less distressed.

An example of an instance may be that of an employee presenting to their co-workers. During the presentation, the person may stutter a word, upon which he or she may worry that other people significantly noticed and think that their perceptions of him or her as a presenter have been tarnished. This cognitive thought propels further anxiety which compounds with further stuttering, sweating, and, potentially, a panic attack.

People with HPD are usually high-functioning, both socially and professionally. They usually have good social skills, despite tending to use them to manipulate others into making them the center of attention. HPD may also affect a person's social and/or romantic relationships, as well as their ability to cope with losses or failures. They may seek treatment for clinical depression when romantic (or other close personal) relationships end.

Individuals with HPD often fail to see their own personal situation realistically, instead dramatizing and exaggerating their difficulties. They may go through frequent job changes, as they become easily bored and may prefer withdrawing from frustration (instead of facing it). Because they tend to crave novelty and excitement, they may place themselves in risky situations. All of these factors may lead to greater risk of developing clinical depression.

Additional characteristics may include:

- Exhibitionist behavior

- Constant seeking of reassurance or approval

- Excessive sensitivity to criticism or disapproval

- Pride of own personality and unwillingness to change, viewing any change as a threat

- Inappropriately seductive appearance or behavior of a sexual nature

- Using somatic symptoms (of physical illness) to garner attention

- A need to be the center of attention

- Low tolerance for frustration or delayed gratification

- Rapidly shifting emotional states that may appear superficial or exaggerated to others

- Tendency to believe that relationships are more intimate than they actually are

- Making rash decisions

- Blaming personal failures or disappointments on others

- Being easily influenced by others, especially those who treat them approvingly

- Being overly dramatic and emotional

Some people with histrionic traits or personality disorder change their seduction technique into a more maternal or paternal style as they age.

Social anxiety disorder (SAD), also known as social phobia, is an anxiety disorder characterized by a significant amount of fear in one or more social situations, causing considerable distress and impaired ability to function in at least some parts of daily life. These fears can be triggered by perceived or actual scrutiny from others.

Physical symptoms often include excessive blushing, excess sweating, trembling, palpitations, and nausea. Stammering may be present, along with rapid speech. Panic attacks can also occur under intense fear and discomfort. Some sufferers may use alcohol or other drugs to reduce fears and inhibitions at social events. It is common for sufferers of social phobia to self-medicate in this fashion, especially if they are undiagnosed, untreated, or both; this can lead to alcoholism, eating disorders or other kinds of substance abuse. SAD is sometimes referred to as an "illness of lost opportunities" where "individuals make major life choices to accommodate their illness". According to ICD-10 guidelines, the main diagnostic criteria of social phobia are fear of being the focus of attention, or fear of behaving in a way that will be embarrassing or humiliating, avoidance and anxiety symptoms. Standardized rating scales can be used to screen for social anxiety disorder and measure the severity of anxiety.

The first line treatment for social anxiety disorder is cognitive behavioral therapy (CBT) with medications recommended only in those who are not interested in therapy. CBT is effective in treating social phobia, whether delivered individually or in a group setting. The cognitive and behavioral components seek to change thought patterns and physical reactions to anxiety-inducing situations. The attention given to social anxiety disorder has significantly increased since 1999 with the approval and marketing of drugs for its treatment. Prescribed medications include several classes of antidepressants: selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), and monoamine oxidase inhibitors (MAOIs). Other commonly used medications include beta blockers and benzodiazepines. It is the most common anxiety disorder with up to 10% of people being affected at some point in their life.

Organic personality disorder (OPD) is not included in the wide variety of group of personality disorders. For this reason, the symptoms and diagnostic criteria of the organic personality disorder are different from those of the mental health disorders, which are included in this various group of personality disorders. According to the Tenth Revision of the International Statistical Classification of Diseases and Related Health Problems ICD-10, it defines the organic personality disorder as the personality change, which can be caused by traumatic brain injury (TBI) that means there are specific brain areas of patients, which have been injured after a very strong accident. Moreover, according to the ICD-10, the organic personality disorder is associated with a "significant alteration of the habitual patterns of premorbid behaviour". Furthermore, organic personality disorder is associated with "personality change due to general medical condition". There are crucial influences on emotions, impulses and personal needs because of this disorder. Thus, all these definitions about the organic personality disorder support that this type of disorder is associated with changes in personality and behaviour.

The ICD-10 includes a diagnostic guideline for the wide group of personality and behavioural disorders. However, every disorder has its own diagnostic criteria. In case of the organic personality disorder, patient has to show at least three of the following diagnostic criteria over a six or more months period. organic personality disorder is associated with a large variety of symptoms, such as deficits in cognitive function, dysfunctional behaviours, psychosis, neurosis, emotional changes, alterations in expression function and irritability. Patients with organic personality disorder can present emotional lability that means their emotional expressions are unstable and fluctuating. In addition, patients show reduction in ability of perseverance with their goals and they express disinhibited behaviours, which are characterised by inappropriate sexual and antisocial actions. For instance, patients can show dissocial behaviours, like stealing. Moreover, according to diagnostic guideline of ICD-10, patients can suffer from cognitive disturbances and they present signs of suspiciousness and paranoid ideas. Additionally, patients may present alteration in process of language production that means there are changes in language rate and flow. Furthermore, patients may show changes in their sexual preference and hyposexuality symptoms.

Another common feature of personality of patients with organic personality disorder is their dysfunctional and maladaptive behaviour that causes serious problems in these patients, because they face problems with pursuit and achievement of their goals. It is worth to be mentioned that patients with organic personality disorder express a feeling of unreasonable satisfaction and euphoria. Also, the patients show aggressive behaviours sometimes and these serious dysfunctions in their behaviour can have effects on their life and their relationships with other people. Specifically patients show intense signs of anger and aggression because of their inability to handle their impulses. The type of this aggression is called "impulsive aggression". Furthermore, it is worth to be mentioned that the pattern of organic personality disorder presents some similarities with pattern of temporal lobe epilepsy (TLE). Specifically patients who suffer from this chronic disorder type of epilepsy, express aggressive behaviours, likewise it happens to patients with organic personality disorder. Another similar symptom between Temporal lobe epilepsy and organic personality disorder is the epileptic seizure. The symptom of epileptic seizure has influence on patients' personality that means it causes behavioural alterations". The Temporal lobe epilepsy (TLE) is associated with the hyperexcitability of the medial temporal lobe (MTL) of patients. Finally, patients with organic personality disorder may present similar symptoms with patients, who suffer from the Huntington's disease as well. The symptoms of apathy and irritability are common between these two groups of patients.

Genes are attributed about a third of general anxiety disorder's variance. Individuals with a genetic predisposition for GAD are more likely to develop GAD, especially in response to a life stressor.

A mnemonic that can be used to remember the characteristics of histrionic personality disorder is shortened as "PRAISE ME":

- Provocative (or seductive) behavior

- Relationships are considered more intimate than they actually are

- Attention-seeking

- Influenced easily by others or circumstances

- Speech (style) wants to impress; lacks detail

- Emotional lability; shallowness

- Make-up; physical appearance is used to draw attention to self

- Exaggerated emotions; theatrical

Generalized anxiety disorder (GAD) is an anxiety disorder characterized by excessive, uncontrollable and often irrational worry, that is, apprehensive expectation about events or activities. This excessive worry often interferes with daily functioning, as individuals with GAD typically anticipate disaster, and are overly concerned about everyday matters such as health issues, money, death, family problems, friendship problems, interpersonal relationship problems, or work difficulties. Individuals may exhibit a variety of physical symptoms, including feeling tired, fidgeting, headaches, numbness in hands and feet, muscle tension, difficulty swallowing, upset stomach, vomiting, diarrhea, breathing difficulty, difficulty concentrating, trembling, irritability, sweating, restlessness, sleeping difficulties, hot flashes, rashes, and inability to fully control the anxiety (ICD-10). These symptoms must be consistent and ongoing, persisting at least six months, for a formal diagnosis of GAD.

Standardized rating scales such as GAD-7 can be used to assess severity of GAD symptoms. GAD is the most common cause of disability in the workplace in the United States.

In a given year, approximately two percent of American adults and European adults experience GAD. Globally about 4% are affected at some point in their life. GAD is seen in women twice as much as men. GAD is also common in individuals with a history of substance abuse and a family history of the disorder. Once GAD develops, it may become chronic, but can be managed or eliminated with proper treatment.

Both diagnostic systems provide a definition and six criteria for a general personality disorder. These criteria should be met by all personality disorder cases before a more specific diagnosis can be made.

The ICD-10 lists these general guideline criteria:

- Markedly disharmonious attitudes and behavior, generally involving several areas of functioning; e.g. affectivity, arousal, impulse control, ways of perceiving and thinking, and style of relating to others;

- The abnormal behavior pattern is enduring, of long standing, and not limited to episodes of mental illness;

- The abnormal behavior pattern is pervasive and clearly maladaptive to a broad range of personal and social situations;

- The above manifestations always appear during childhood or adolescence and continue into adulthood;

- The disorder leads to considerable personal distress but this may only become apparent late in its course;

- The disorder is usually, but not invariably, associated with significant problems in occupational and social performance.

The ICD adds: "For different cultures it may be necessary to develop specific sets of criteria with regard to social norms, rules and obligations."

In DSM-5, any personality disorder diagnosis must meet the following criteria:

- An enduring pattern of inner experience and behavior that deviates markedly from the expectations of the individual’s culture. This pattern is manifested in two (or more) of the following areas:

1. Cognition (i.e., ways of perceiving and interpreting self, other people, and events).

2. Affectivity (i.e., the range, intensity, lability, and appropriateness of emotional response).

3. Interpersonal functioning.

4. Impulse control.

- The enduring pattern is inflexible and pervasive across a broad range of personal and social situations.

- The enduring pattern leads to clinically significant distress or impairment in social, occupational, or other important areas of functioning.

- The pattern is stable and of long duration, and its onset can be traced back at least to adolescence or early adulthood.

- The enduring pattern is not better explained as a manifestation or consequence of another mental disorder.

- The enduring pattern is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication) or another medical condition (e.g., head trauma).

Personality disorders (PD) are a class of mental disorders characterized by enduring maladaptive patterns of behavior, cognition, and inner experience, exhibited across many contexts and deviating markedly from those accepted by the individual's culture. These patterns develop early, are inflexible, and are associated with significant distress or disability. The definitions may vary somewhat, according to source. Official criteria for diagnosing personality disorders are listed in the "Diagnostic and Statistical Manual of Mental Disorders" (DSM) and the of the "International Classification of Diseases" (ICD). The DSM-5 lists personality disorders in the same way as other mental disorders, rather than on a separate 'axis', as previously.

Personality, defined psychologically, is the set of enduring behavioral and mental traits that distinguish between individual humans. Hence, personality disorders are defined by experiences and behaviors that differ from societal norms and expectations. Those diagnosed with a personality disorder may experience difficulties in cognition, emotiveness, interpersonal functioning, or impulse control. In general, personality disorders are diagnosed in 40–60% of psychiatric patients, making them the most frequent of psychiatric diagnoses.

Personality disorders are characterized by an enduring collection of behavioral patterns often associated with considerable personal, social, and occupational disruption. Personality disorders are also inflexible and pervasive across many situations, largely due to the fact that such behavior may be ego-syntonic (i.e. the patterns are consistent with the ego integrity of the individual) and are therefore perceived to be appropriate by that individual. This behavior can result in maladaptive coping skills and may lead to personal problems that induce extreme anxiety, distress, or depression. These behaviour patterns are typically recognized in adolescence, the beginning of adulthood or sometimes even childhood and often have a pervasive negative impact on the quality of life.

Many issues occur with classifying a personality disorder. Because the theory and diagnosis of personality disorders occur within prevailing cultural expectations, their validity is contested by some experts on the basis of inevitable subjectivity. They argue that the theory and diagnosis of personality disorders are based strictly on social, or even sociopolitical and economic considerations.

Pseudoneurotic schizophrenia is a postulated mental disorder categorized by the presence of two or more symptoms of mental illness such as anxiety, hysteria, and phobic or obsessive-compulsive neuroses. It is often acknowledged as a personality disorder. Patients generally display salient anxiety symptoms that disguise an underlying psychotic disorder.

In the 1940s, psychiatrists Paul Hoch and Philip Polatin created the term pseudoneurotic schizophrenia. This mental illness, however, is no longer acknowledged as a clinical entity. In 1972 it went on to be called borderline personality disorder, a term coined by Otto Friedmann Kernberg, which referred to an expansive range of issues.

Pseudoneurotic schizophrenia is in the Russian adapted version of the ICD-10 (code F21.3).

Diffuse anxiety is stimulated by a minor catalyst and may persist long after the catalyst disappears.

Major depression significantly affects a person's family and personal relationships, work or school life, sleeping and eating habits, and general health. Its impact on functioning and well-being has been compared to that of other chronic medical conditions such as diabetes.

A person having a major depressive episode usually exhibits a very low mood, which pervades all aspects of life, and an inability to experience pleasure in activities that were formerly enjoyed. Depressed people may be preoccupied with, or ruminate over, thoughts and feelings of worthlessness, inappropriate guilt or regret, helplessness, hopelessness, and self-hatred. In severe cases, depressed people may have symptoms of psychosis. These symptoms include delusions or, less commonly, hallucinations, usually unpleasant. Other symptoms of depression include poor concentration and memory (especially in those with melancholic or psychotic features), withdrawal from social situations and activities, reduced sex drive, irritability, and thoughts of death or suicide. Insomnia is common among the depressed. In the typical pattern, a person wakes very early and cannot get back to sleep. Hypersomnia, or oversleeping, can also happen. Some antidepressants may also cause insomnia due to their stimulating effect.

A depressed person may report multiple physical symptoms such as fatigue, headaches, or digestive problems; physical complaints are the most common presenting problem in developing countries, according to the World Health Organization's criteria for depression. Appetite often decreases, with resulting weight loss, although increased appetite and weight gain occasionally occur. Family and friends may notice that the person's behavior is either agitated or lethargic. Older depressed people may have cognitive symptoms of recent onset, such as forgetfulness, and a more noticeable slowing of movements. Depression often coexists with physical disorders common among the elderly, such as stroke, other cardiovascular diseases, Parkinson's disease, and chronic obstructive pulmonary disease.

Depressed children may often display an irritable mood rather than a depressed mood, and show varying symptoms depending on age and situation. Most lose interest in school and show a decline in academic performance. They may be described as clingy, demanding, dependent, or insecure. Diagnosis may be delayed or missed when symptoms are interpreted as normal moodiness.

Neurosis is a class of functional mental disorders involving chronic distress but neither delusions nor hallucinations. The term is no longer used by the professional psychiatric community in the United States, having been eliminated from the "Diagnostic and Statistical Manual of Mental Disorders" in 1980 with the publication of DSM III. It is still used in the .

Neurosis should not be mistaken for psychosis, which refers to a loss of touch with reality. Neither should it be mistaken for neuroticism, a fundamental personality trait proposed in the big Five personality traits theory.

Psychiatric co-morbidity in ORS is reported. Depression, which is often severe, may be a result of ORS, or may be pre-existing. Personality disorders, especially cluster C, and predominantly the avoidant type, may exist with ORS. bipolar disorder, schizophrenia, hypochondriasis, alcohol, drug abuse and obsessive compulsive disorder.

Major depression frequently co-occurs with other psychiatric problems. The 1990–92 "National Comorbidity Survey" (US) reports that half of those with major depression also have lifetime anxiety and its associated disorders such as generalized anxiety disorder. Anxiety symptoms can have a major impact on the course of a depressive illness, with delayed recovery, increased risk of relapse, greater disability and increased suicide attempts. There are increased rates of alcohol and drug abuse and particularly dependence, and around a third of individuals diagnosed with ADHD develop comorbid depression. Post-traumatic stress disorder and depression often co-occur. Depression may also coexist with attention deficit hyperactivity disorder (ADHD), complicating the diagnosis and treatment of both. Depression is also frequently comorbid with alcohol abuse and personality disorders.

Depression and pain often co-occur. One or more pain symptoms are present in 65% of depressed patients, and anywhere from 5 to 85% of patients with pain will be suffering from depression, depending on the setting; there is a lower prevalence in general practice, and higher in specialty clinics. The diagnosis of depression is often delayed or missed, and the outcome can worsen if the depression is noticed but completely misunderstood.

Depression is also associated with a 1.5- to 2-fold increased risk of cardiovascular disease, independent of other known risk factors, and is itself linked directly or indirectly to risk factors such as smoking and obesity. People with major depression are less likely to follow medical recommendations for treating and preventing cardiovascular disorders, which further increases their risk of medical complications. In addition, cardiologists may not recognize underlying depression that complicates a cardiovascular problem under their care.

Conversion disorder is now contained under the umbrella term functional neurological symptom disorder. In cases of conversion disorder, there is a psychological stressor.

The diagnostic criteria for functional neurological symptom disorder, as set out in DSM-V, are:

Specify type of symptom or deficit as:

- With weakness or paralysis

- With abnormal movement (e.g. tremor, dystonic movement, myoclonus, gait disorder)

- With swallowing symptoms

- With speech symptoms (e.g. dysphonia, slurred speech)

- With attacks or seizures

- With amnesia or memory loss

- With special sensory symptom (e.g. visual, olfactory, or hearing disturbance)

- With mixed symptoms.

Specify if:

- Acute episode: symptoms present for less than six months

- Persistent: symptoms present for six months or more.

Specify if:

- Psychological stressor (conversion disorder)

- No psychological stressor (functional neurological symptom disorder)

Conversion disorder begins with some stressor, trauma, or psychological distress. Usually the physical symptoms of the syndrome affect the senses or movement. Common symptoms include blindness, partial or total paralysis, inability to speak, deafness, numbness, difficulty swallowing, incontinence, balance problems, seizures, tremors, and difficulty walking. These symptoms are attributed to conversion disorder when a medical explanation for the afflictions cannot be found. Symptoms of conversion disorder usually occur suddenly. Conversion disorder is typically seen in individuals aged 10 to 35, and affects between 0.011% and 0.5% of the general population.

Conversion disorder can present with motor or sensory symptoms including any of the following:

Motor symptoms or deficits:

- Impaired coordination or balance

- Weakness/paralysis of a limb or the entire body (hysterical paralysis or motor conversion disorders)

- Impairment or loss of speech (hysterical aphonia)

- Difficulty swallowing (dysphagia) or a sensation of a lump in the throat

- Urinary retention

- Psychogenic non-epileptic seizures or convulsions

- Persistent dystonia

- Tremor, myoclonus or other movement disorders

- Gait problems (astasia-abasia)

- Loss of consciousness (fainting)

Sensory symptoms or deficits:

- Impaired vision (hysterical blindness), double vision

- Impaired hearing (deafness)

- Loss or disturbance of touch or pain sensation

Conversion symptoms typically do not conform to known anatomical pathways and physiological mechanisms. It has sometimes been stated that the presenting symptoms tend to reflect the patient's own understanding of anatomy and that the less medical knowledge a person has, the more implausible are the presenting symptoms. However, no systematic studies have yet been performed to substantiate this statement.

Persons with ORS tend to develop a behavior pattern of avoidance of social activities and progressive social withdrawal. They often avoid travel, dating, relationships, break off engagements and avoid family activities. Due to shame and embarrassment, they may avoid school or work, or repeatedly change jobs and move to another town. Significant developments may occur such as loss of employment, divorce, becoming housebound, psychiatric hospitalization, and suicide attempts. According to some reports, 74% of persons with ORS avoid social situations, 47% avoid work, academic or other important activities, 40% had been housebound for at least 1 week because of ORS, and 31.6% had experienced psychiatric hospitalization. With regards suicide, reports range from 43-68% with suicidal ideation, and 32% with a history of at least one suicide attempt. 5.6% successfully committed suicide.

According to psychoanalytic theory, neuroses may be rooted in ego defense mechanisms, but the two concepts are not synonymous. Defense mechanisms are a normal way of developing and maintaining a consistent sense of self (i.e., an ego). But only those thoughts and behaviors that produce difficulties in one's life should be called neuroses.

A neurotic person experiences emotional distress and unconscious conflict, which are manifested in various physical or mental illnesses. The definitive symptom is anxiety.

Neurotic tendencies are common and may manifest themselves as acute or chronic anxiety, depression, an obsessive–compulsive disorder, a phobia, or a personality disorder.

The psychiatric history frequently contains multiple previous diagnoses of various disorders and treatment failures. The most common presenting complaint of DID is depression, with headaches being a common neurological symptom. Comorbid disorders can include substance abuse, eating disorders, anxiety, post traumatic stress disorder (PTSD), and personality disorders. A significant percentage of those diagnosed with DID have histories of borderline personality disorder and bipolar disorder. Further, data supports a high level of psychotic symptoms in individuals with DID, and that both individuals diagnosed with schizophrenia and those diagnosed with DID have histories of trauma. Other disorders that have been found to be comorbid with DID are somatization disorders, major depressive disorder, as well as history of a past suicide attempt, in comparison to those without a DID diagnosis. Individuals diagnosed with DID demonstrate the highest hypnotizability of any clinical population. The large number of symptoms presented by individuals diagnosed with DID has led some clinicians to suggest that, rather than being a separate disorder, diagnosis of DID is actually an indication of the severity of the other disorders diagnosed in the patient.

The DSM-IV-TR states that acts of self-mutilation, impulsivity, and rapid changes in interpersonal relationships "may warrant a concurrent diagnosis of borderline personality disorder". Steven Lynn and colleagues have suggested that the significant overlap between BPD and DID may be a contributing factor to the development of therapy induced DID, in that the suggestion of hidden alters by therapists who propose a diagnosis of DID provides an explanation to patients for the behavioral instability, self-mutilation, unpredictable mood changes and actions they experience. In 1993 a group of researchers reviewed both DID and borderline personality disorder (BPD), concluding that DID was an epiphenomenon of BPD, with no tests or clinical description capable of distinguishing between the two. Their conclusions about the empirical proof of DID were echoed by a second group, who still believed the diagnosis existed, but while the knowledge to date did not justify DID as a separate diagnosis, it also did not disprove its existence. Reviews of medical records and psychological tests indicated that the majority of DID patients could be diagnosed with BPD instead, though about a third could not, suggesting that DID does exist but may be over-diagnosed. Between 50 and 66% of patients also meet the criteria for BPD, and nearly 75% of patients with BPD also meet the criteria for DID, with considerable overlap between the two conditions in terms of personality traits, cognitive and day-to-day functioning, and ratings by clinicians. Both groups also report higher rates of physical and sexual abuse than the general population, and patients with BPD also score highly on measures of dissociation. Even using strict diagnostic criteria, it can be difficult to distinguish between dissociative disorders and BPD (as well as bipolar disorder and schizophrenia), though the presence of comorbid anxiety disorders may help.

There are various other psychological issues that may factor into anorexia nervosa, some fulfill the criteria for a separate Axis I diagnosis or a personality disorder which is coded Axis II and thus are considered comorbid to the diagnosed eating disorder. Axis II disorders are subtyped into 3 "clusters", A, B and C. The causality between personality disorders and eating disorders has yet to be fully established. Some people have a previous disorder which may increase their vulnerability to developing an eating disorder. Some develop them afterwards. The severity and type of eating disorder symptoms have been shown to affect comorbidity. These comorbid disorders themselves have multiple differential diagnoses, such as depression which may be caused by such disparate causes such as Lyme disease or hypothyroidism.

- Body dysmorphic disorder (BDD) is listed as a somatoform disorder that affects up to 2% of the population. BDD is characterized by excessive rumination over an actual or perceived physical flaw. BDD has been diagnosed equally among men and women. While BDD has been misdiagnosed as anorexia nervosa, it also occurs comorbidly in 25% to 39% of AN cases.

BDD is a chronic and debilitating condition which may lead to social isolation, major depression, suicidal ideation and attempts. Neuroimaging studies to measure response to facial recognition have shown activity predominately in the left hemisphere in the left lateral prefrontal cortex, lateral temporal lobe and left parietal lobe showing hemispheric imbalance in information processing. There is a reported case of the development of BDD in a 21 year old male following an inflammatory brain process. Neuroimaging showed the presence of new atrophy in the frontotemporal region.

- Emetophobia is an anxiety disorder characterized by an intense fear of vomiting. A person so afflicted may develop rigorous standards of food hygiene, such as not touching food with their hands. They may become socially withdrawn to avoid situations which in their perception may make them vomit. Many who suffer from emetophobia are diagnosed with anorexia or self-starvation. In severe cases of emetophobia they may drastically reduce their food intake.

- Food avoidance emotional disorder is an eating disorder that affects children which involves a fear of eating which is not accompanied by a fear of weight gain which may be misdiagnosed as anorexia nervosa.

- phagophobia is an anxiety disorder characterized by a fear of eating, it is usually initiated by an adverse experience while eating such as choking or vomiting. Individuals with this disorder may present with complaints of pain while swallowing. There have been cases of it being misdiagnosed as AN. A similar phobic anxiety disorder, swallowing phobia may also lead to a misdiagnosis of anorexia nervosa; such individuals do not want to lose weight but typically want to put weight back on that they have lost due to their phobia.

The distinction between the diagnoses of anorexia nervosa, bulimia nervosa and eating disorder not otherwise specified (EDNOS) is often difficult to make as there is considerable overlap between patients diagnosed with these conditions. Seemingly minor changes in a patient's overall behavior or attitude can change a diagnosis from "anorexia: binge-eating type" to bulimia nervosa. It is not unusual for a person with an eating disorder to "move through" various diagnoses as his or her behavior and beliefs change over time.