Pan-Neurosis is the existence of multiple neurotic symptoms such as:

- obsessions

- compulsions

- phobias

- hysteria

- depression

- hypochondriasis

- depersonalization

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

The following specifiers for schizophreniform disorder may be used to indicate the presence or absence of features that may be associated with a better prognosis:

- With Good Prognostic Features, used if at least two of the following features are present:

- Onset of prominent psychotic symptoms within 4 weeks of the first noticeable change in usual behavior or functioning

- Confusion or perplexity at the height of the psychotic episode

- Good premorbid social and occupational functioning

- Absence of blunted or flat affect

- Without Good Prognostic Features, used if two or more of the above features have not been present.

The presence of negative symptoms and poor eye contact both appear to be prognostic of a poor outcome. Many of the anatomic and functional changes seen in the brains of patients with schizophrenia also occur in patients with schizophreniform disorder. However, at present there is no consensus among scientists regarding whether or not ventricular enlargement, which is a poor prognostic factor in schizophrenia, has any prognostic value in patients with schizophreniform disorder. According to the American Psychiatric Association, approximately two-thirds of patients diagnosed with "provisional" schizophreniform disorder are subsequently diagnosed with schizophrenia; the remaining keep a diagnosis of schizophreniform disorder.

Schizophreniform disorder is a type of mental illness that is characterized by psychosis and closely related to schizophrenia. Both schizophrenia and schizophreniform disorder, as defined by the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-IV-TR), have the same symptoms and essential features except for two differences: the level of functional impairment and the duration of symptoms. Impairment in social, occupational, or academic functioning is usually present in schizophrenia, particularly near the time of first diagnosis, but such impairment may or may not be present in schizophreniform disorder. In schizophreniform disorder, the symptoms (including prodromal, active, and residual phases) must last at least 1 month but not more than 6 months, while in schizophrenia the symptoms must be present for a minimum of 6 months.

If the symptoms have persisted for at least one month, a provisional diagnosis of schizophreniform disorder can be made while waiting to see if recovery occurs. If the symptoms resolve within 6 months of onset, the provisional qualifier is removed from the diagnosis. However, if the symptoms persist for 6 months or more, the diagnosis of schizophreniform disorder must be revised. The diagnosis of brief psychotic disorder may be considered when the duration of symptoms is less than one month.

The main symptoms of both schizophreniform disorder and schizophrenia may include:

- delusions,

- hallucinations,

- disorganized speech resulting from formal thought disorder,

- disorganized or catatonic behavior, and negative symptoms, such as

- an inability to feel a range of emotions (flat affect),

- an inability to experience pleasure (anhedonia),

- impaired or decreased speech (aphasia),

- a lack of desire to form relationships (asociality), and

- a lack of motivation (avolition).

Schizoaffective disorder is defined by "mood disorder-free psychosis" in the context of a long-term psychotic and mood disorder. Psychosis must meet criterion A for schizophrenia which may include delusions, hallucinations, disorganized speech, thinking or behavior and negative symptoms. Both delusions and hallucinations are classic symptoms of psychosis. Delusions are false beliefs which are strongly held despite evidence to the contrary. Beliefs should not be considered delusional if they are in keeping with cultural beliefs. Delusional beliefs may or may not reflect mood symptoms (for example, someone experiencing depression may or may not experience delusions of guilt). Hallucinations are disturbances in perception involving any of the five senses, although auditory hallucinations (or "hearing voices") are the most common. A lack of responsiveness or negative symptoms include alogia (lack of spontaneous speech), blunted affect (reduced intensity of outward emotional expression), avolition (loss of motivation), and anhedonia (inability to experience pleasure). Negative symptoms can be more lasting and more debilitating than positive symptoms of psychosis.

Mood symptoms are of mania, hypomania, mixed episode, or depression, and tend to be episodic rather than continuous. A mixed episode represents a combination of symptoms of mania and depression at the same time. Symptoms of mania include elevated or irritable mood, grandiosity (inflated self-esteem), agitation, risk-taking behavior, decreased need for sleep, poor concentration, rapid speech, and racing thoughts. Symptoms of depression include low mood, apathy, changes in appetite or weight, disturbances in sleep, changes in motor activity, fatigue, guilt or feelings of worthlessness, and suicidal thinking.

Individuals with schizophrenia may experience hallucinations (most reported are hearing voices), delusions (often bizarre or persecutory in nature), and disorganized thinking and speech. The last may range from loss of train of thought, to sentences only loosely connected in meaning, to speech that is not understandable known as word salad. Social withdrawal, sloppiness of dress and hygiene, and loss of motivation and judgment are all common in schizophrenia.

Distortions of self-experience such as feeling as if one's thoughts or feelings are not really one's own to believing thoughts are being inserted into one's mind, sometimes termed passivity phenomena, are also common. There is often an observable pattern of emotional difficulty, for example lack of responsiveness. Impairment in social cognition is associated with schizophrenia, as are symptoms of paranoia. Social isolation commonly occurs. Difficulties in working and long-term memory, attention, executive functioning, and speed of processing also commonly occur. In one uncommon subtype, the person may be largely mute, remain motionless in bizarre postures, or exhibit purposeless agitation, all signs of catatonia. People with schizophrenia often find facial emotion perception to be difficult. It is unclear if the phenomenon called "thought blocking", where a talking person suddenly becomes silent for a few seconds to minutes, occurs in schizophrenia.

About 30 to 50 percent of people with schizophrenia fail to accept that they have an illness or comply with their recommended treatment. Treatment may have some effect on insight.

People with schizophrenia may have a high rate of irritable bowel syndrome but they often do not mention it unless specifically asked. Psychogenic polydipsia, or excessive fluid intake in the absence of physiological reasons to drink, is relatively common in people with schizophrenia.

The condition is also known as hebephrenia, named after the Greek term for "adolescence" – "ἥβη" (hḗbē), and possibly the Ancient Greek goddess of youth, Hebe, daughter of Hera. The term refers to the ostensibly more prominent appearance of the disorder in persons around puberty.

The prominent characteristics of this form are disorganized behavior and speech (see formal thought disorder), including loosened associations and schizophasia ("word salad"), and flat or inappropriate affect. In addition, psychiatrists must rule out any possible sign of catatonic schizophrenia.

The most prominent features of disorganized schizophrenia are not delusions and hallucinations, as they are in paranoid schizophrenia, although fragmentary delusions, unsystemized and often hypochondriacal, and hallucinations may be present. A person with disorganized schizophrenia may also experience behavioral disorganization, which may impair his or her ability to carry out daily activities such as showering or eating.

The emotional responses of such people often seem strange or inappropriate. Inappropriate facial responses may be common, and behavior is sometimes described as 'silly', such as inappropriate laughter. Sometimes, there is a complete lack of emotion, including anhedonia (the lack of pleasure), and avolition (a lack of motivation). Some of these features are also present in other types of schizophrenia, but they are most prominent in disorganized schizophrenia.

Schizophrenia is often described in terms of positive and negative (or deficit) symptoms. "Positive symptoms" are those that most individuals do not normally experience, but are present in people with schizophrenia. They can include delusions, disordered thoughts and speech, and tactile, auditory, visual, olfactory and gustatory hallucinations, typically regarded as manifestations of psychosis. Hallucinations are also typically related to the content of the delusional theme. Positive symptoms generally respond well to medication.

"Negative symptoms" are deficits of normal emotional responses or of other thought processes, and are less responsive to medication. They commonly include flat expressions or little emotion, poverty of speech, inability to experience pleasure, lack of desire to form relationships, and lack of motivation. Negative symptoms appear to contribute more to poor quality of life, functional ability, and the burden on others than positive symptoms do. People with greater negative symptoms often have a history of poor adjustment before the onset of illness, and response to medication is often limited.

The validity of the positive and negative construct has been challenged by factor analysis studies observing a three dimension grouping of symptoms. While different terminology is used, a dimension for hallucinations, a dimension for disorganization, and a dimension for negative symptoms are usually described.

The main symptoms of paraphrenia are paranoid delusions and hallucinations. The delusions often involve the individual being the subject of persecution, although they can also be erotic, hypochondriacal, or grandiose in nature. The majority of hallucinations associated with paraphrenia are auditory, with 75% of patients reporting such an experience; however, visual, tactile, and olfactory hallucinations have also been reported. The paranoia and hallucinations can combine in the form of “threatening or accusatory voices coming from neighbouring houses [and] are frequently reported by the patients as disturbing and undeserved". Patients also present with a lack of symptoms commonly found in other mental disorders similar to paraphrenia. There is no significant deterioration of intellect, personality, or habits and patients often remain clean and mostly self-sufficient. Patients also remain oriented well in time and space.

Paraphrenia is different from schizophrenia because, while both disorders result in delusions and hallucinations, individuals with schizophrenia exhibit changes and deterioration of personality whereas individuals with paraphrenia maintain a well-preserved personality and affective response.

Schizophrenia is a mental disorder that is expressed in abnormal mental functions and disturbed behavior.

The signs and symptoms of childhood schizophrenia are nearly the same as adult-onset schizophrenia. Some of the earliest signs that a young child may develop schizophrenia are lags in language and motor development. Some children engage in activities such as flapping the arms or rocking, and may appear anxious, confused, or disruptive on a regular basis. Children may experience symptoms such as hallucinations, but these are often difficult to differentiate from just normal imagination or child play. It is often difficult for children to describe their hallucinations or delusions, making very early-onset schizophrenia especially difficult to diagnose in the earliest stages. The cognitive abilities of children with schizophrenia may also often be lacking, with 20% of patients showing borderline or full intellectual disability.

Very early-onset schizophrenia refers to onset before the age of thirteen. The prodromal phase, which precedes psychotic symptoms, is characterized by deterioration in school performance, social withdrawal, disorganized or unusual behavior, a decreased ability to perform daily activities, a deterioration in self-care skills, bizarre hygiene and eating behaviors, changes in affect, a lack of impulse control, hostility and aggression, and lethargy.

Auditory hallucinations are the most common "positive symptom" in children. Positive symptoms have come to mean psychopathological disorders that are actively expressed, such as delusions, hallucinations, thought disorder etc.). A child's auditory hallucinations may include voices that are conversing with each other or voices that are speaking directly to the children themselves. Many children with auditory hallucinations believe that if they do not listen to the voices, the voices will harm them or someone else. Tactile and visual hallucinations seem relatively rare. The children often attribute the hallucinatory voices to a variety of beings, including family members or other people, evil forces ("the Devil", "a witch", "a spirit"), animals, characters from horror movies (Bloody Mary, Freddy Krueger) and less clearly recognizable sources ("bad things," "the whispers"). Command auditory hallucinations (also known as imperative hallucinations) were common and experienced by more than ½ of the group in a research at the Bellevue Hospital Center's Children's Psychiatric Inpatient Unit. And voices repeat and repeat: "Kill somebody!", "Kill her, kill her!". Delusions are reported in more than half of children with schizophrenia, but they are usually less complex than those of adults. Delusions often connected with hallucinatory experiences.. In a research delusions were characterized as persecutory for the most part, but some children reported delusions of control. Many said they were being tortured by the beings causing their visual and auditory hallucinations, some thought that if they disobeying their voices would cause them harm.

Some degree of thought disorder was observed in a test group of children in Bellevue Hospital. They displayed illogicality, tangentialiry (a serious disturbance in the associative thought process), and loosening of associations.

Negative ("deficit") symptoms in schizophrenia reflect mental deficit states such as apathy and aboulia, avolition, flattened affect, asthenia etc.

Paranoid schizophrenia manifests itself in an array of symptoms. Common symptoms for paranoid schizophrenia include auditory hallucinations (hearing voices) and paranoid delusions (believing everyone is out to cause the sufferer harm). However, two of the symptoms separate this form of schizophrenia from other forms.

One criterion for separating paranoid schizophrenia from other types is delusion. A delusion is a belief that is held strongly even when the evidence shows otherwise. Some common delusions associated with paranoid schizophrenia include, “believing that the government is monitoring every move you make, or that a co-worker is poisoning your lunch." In all but rare cases, these beliefs are irrational, and can cause the person holding them to behave abnormally. Another frequent type of delusion is a delusion of grandeur, or the “fixed, false belief that one possesses superior qualities such as genius, fame, omnipotence, or wealth." Common ones include, “the belief that you can fly, that you're famous, or that you have a relationship with a famous person."

Another criterion present in patients with paranoid schizophrenia is auditory hallucinations, in which the person hears voices or sounds that are not really present. The patient will sometimes hear multiple voices and the voices can either be talking to the patient or to one another. These voices can influence the patient to behave in a particular manner. Researchers at the Mayo Foundation for Medical Education and Research provide the following description: “They [the voices] may make ongoing criticisms of what you’re thinking or doing, or make cruel comments about your real or imagined faults. Voices may also command you to do things that can be harmful to yourself or to others." A patient exhibiting these auditory hallucinations may be observed "talking to them" because the person believes that the voices represent people who are present.

Early diagnosis is critical for the successful treatment of schizophrenia.

Depressive Disorder Not Otherwise Specified (DD-NOS) is designated by the code "311" in the DSM-IV for depressive disorders that are impairing but do not fit any of the officially specified diagnoses. According to the DSM-IV, DD-NOS encompasses "any depressive disorder that does not meet the criteria for a specific disorder." In the DSM-5, it is called unspecified depressive disorder.

Examples of disorders in this category include those sometimes described as minor depressive disorder and recurrent brief depression.

"Depression" refers to a spectrum of disturbances in mood that vary from mild to severe and from short periods to constant illness. DD-NOS is diagnosed if a patients symptoms fail to meet the criteria more common depressive disorders such as major depressive disorder or dysthymia. Although DD-NOS shares similar symptoms to dysthymia, dysthymia is classified by a period of at least 2 years of constantly recurring depressed mood, where as DD-NOS is classified by much shorter periods of depressed moods.

For most people who suffer the condition, their life will be significantly affected. DD-NOS can make many aspects of a person's daily life difficult to manage, inhibiting their ability to enjoy the things that used to make them happy. Sufferers of the disorder tend to isolate themselves from their friends and families, lose interest in some activities, and experience behavioural changes and sleeping disorders. Some sufferers also experience suicidal tendencies or suicide attempts. In addition to having these symptoms, a diagnosis of DD-NOS will only be made if the symptoms cause significant distress or impairment in social, occupational, or other important areas of functioning. For the diagnosis to be accurate, a psychiatrist is required to spend extensive time with the patient.

Symptoms of the disorder may arise due to several reasons. These include:

- Distress due to medical conditions

- Environmental effects and situations

However, the effects of drugs or medication or bereavement are not classified under the diagnosis.

A person will not be diagnosed with the condition if they have or have had any of the following: a major depressive episode, manic episode, mixed episode or hypomanic episode.

A diagnosis of the disorder will look like: "Depressive Disorder NOS 311".

In the American Psychiatric Association's DSM-5, schizotypal personality disorder is defined as a "pervasive pattern of social and interpersonal deficits marked by acute discomfort with, and reduced capacity for, close relationships as well as by cognitive or perceptual distortions and eccentricities of behavior, beginning by early adulthood and present in a variety of contexts."

At least five of the following symptoms must be present: ideas of reference, strange beliefs or magical thinking, abnormal perceptual experiences, strange thinking and speech, paranoia, inappropriate or constricted affect, strange behavior or appearance, lack of close friends, and excessive social anxiety that does not abate and stems from paranoia rather than negative judgments about self. These symptoms must not occur only during the course of a disorder with similar symptoms (such as schizophrenia or autism spectrum disorder).

Schizoaffective disorder (SZA, SZD or SAD) is a mental disorder characterized by abnormal thought processes and deregulated emotions. The diagnosis is made when the person has features of both schizophrenia and a mood disorder—either bipolar disorder or depression—but does not strictly meet diagnostic criteria for either alone. The bipolar type is distinguished by symptoms of mania, hypomania, or mixed episode; the depressive type by symptoms of depression only. Common symptoms of the disorder include hallucinations, paranoid delusions, and disorganized speech and thinking. The onset of symptoms usually begins in young adulthood, currently with an uncertain lifetime prevalence because the disorder was redefined, but DSM-IV prevalence estimates were less than 1 percent of the population, in the range of 0.5 to 0.8 percent. Diagnosis is based on observed behavior and the person's reported experiences.

Genetics, neurobiology, early and current environment, behavioral, social, and experiential components appear to be important contributory factors; some recreational and prescription drugs may cause or worsen symptoms. No single isolated organic cause has been found, but extensive evidence exists for abnormalities in the metabolism of tetrahydrobiopterin (BH4), dopamine, and glutamic acid in people with schizophrenia, psychotic mood disorders, and schizoaffective disorder. People with schizoaffective disorder are likely to have co-occurring conditions, including anxiety disorders and substance use disorder. Social problems such as long-term unemployment, poverty and homelessness are common. The average life expectancy of people with the disorder is shorter than those without it, due to increased physical health problems from an absence of health promoting behaviors such as a sedentary lifestyle, and a higher suicide rate.

The mainstay of current treatment is antipsychotic medication combined with mood stabilizer medication or antidepressant medication, or both. There is growing concern by some researchers that antidepressants may increase psychosis, mania, and long-term mood episode cycling in the disorder. When there is risk to self or others, usually early in treatment, hospitalization may be necessary. Psychiatric rehabilitation, psychotherapy, and vocational rehabilitation are very important for recovery of higher psychosocial function. As a group, people with schizoaffective disorder diagnosed using DSM-IV and criteria have a better outcome than people with schizophrenia, but have variable individual psychosocial functional outcomes compared to people with mood disorders, from worse to the same. Outcomes for people with DSM-5 diagnosed schizoaffective disorder depend on data from prospective cohort studies, which haven't been completed yet.

In DSM-5 and ICD-10, schizoaffective disorder is in the same diagnostic class as schizophrenia, but not in the same class as mood disorders. The diagnosis was introduced in 1933, and its definition was slightly changed in the DSM-5, published in May 2013, because the DSM-IV schizoaffective disorder definition leads to excessive misdiagnosis. The changes made to the schizoaffective disorder definition were intended to make the DSM-5 diagnosis more consistent (or reliable), and to substantially reduce the use of the diagnosis. Additionally, the DSM-5 schizoaffective disorder diagnosis can no longer be used for first episode psychosis.

Schizotypal personality disorder (STPD) or schizotypal disorder is a mental disorder characterized by severe social anxiety, thought disorder, paranoid ideation, derealization, transient psychosis, and often unconventional beliefs. People with this disorder feel extreme discomfort with maintaining close relationships with people, mainly because they think that their peers harbor negative thoughts towards them, so they avoid forming them. Peculiar speech mannerisms and odd modes of dress are also symptoms of this disorder. Those with STPD may react oddly in conversations, not respond or talk to themselves.

They frequently interpret situations as being strange or having unusual meaning for them; paranormal and superstitious beliefs are common. Such people frequently seek medical attention for anxiety or depression instead of their personality disorder. Schizotypal personality disorder occurs in approximately 3% of the general population and is more common in males.

The term ""schizotype"" was first coined by Sandor Rado in 1956 as an abbreviation of ""schizophrenic phenotype"". STPD is classified as a cluster A personality disorder ("odd or eccentric disorders") and is considered to be the most impairing disorder in this cluster.

Because the nature of acute schizophrenia is similar to depression, it is difficult to differentiate normal levels of depression in patients with schizophrenia from depressive levels in post-schizophrenic depression. "Prominent subjectively low mood, suggesting depression, and prominent blunting of affect, suggesting negative symptoms, are the two features which are most helpful in differentiating [schizophrenia and depression]." A number of researchers believe that depression is actually a symptom of schizophrenia that has been hidden by the psychosis. However, symptoms usually arise after the first psychotic episodes if they will arise at all. Officially, diagnosing post-schizophrenia depression in a patient requires for the patient to be experiencing a depressive episode of either short or long term following the overcoming of schizophrenia. The patient must still demonstrate some schizophrenic symptoms but those symptoms must no longer be the focus of the illness. Typically, the depressive symptoms are not severe enough to be classified as a severe depressive episode. Formally, diagnosis entails the patient having had schizophrenia within the past year, a number of schizophrenic symptoms, and depression being present for two weeks or more. Mild schizophrenic signs may be withdrawing socially, agitation or hostility, and irregular sleep such as in the case of insomnia and hypersomnia.

The DSM-IV criteria (note there may be new criteria for the condition under the DSM-5) for the diagnosis of schizophrenia require the presence of symptoms for certain periods of time. A person must exhibit two or more core symptoms for a minimum of one month, such as delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, or negative symptoms. There also must be significant impairment for the person at work, with academic performance, interpersonal relationships, and/or the ability to take care of oneself. These symptoms must continue for a minimum of six months, with the first symptoms continuing for at least one month. Paranoid schizophrenia is differentiated by the presence of hallucinations and delusions involving the perception of persecution or grandiosity in one's beliefs about the world.

People with paranoid schizophrenia are often more articulate or "normal" seeming than other people with schizophrenia, such as disorganized schizophrenia (hebephrenia)-afflicted individuals. The diagnosis of paranoid schizophrenia is given based on the presence of bizarre delusions or hallucinations that defy the natural laws of basic logical thought processes, or thought disorders and withdrawal due to these thoughts and delusions. The paranoid subset of schizophrenia tends to have a better prognosis than other subtypes (disorganized and simple–type in particular), as the intellect and personality are relatively preserved, thus enabling a greater degree of cognitive and interpersonal functioning.

With the removal of the subtypes of schizophrenia in DSM-5, paranoid schizophrenia will no longer be used as a diagnostic category. If a person is exhibiting symptoms of schizophrenia, including symptoms of paranoid type, they will simply be diagnosed with schizophrenia and will be treated with antipsychotics based on their individual symptoms.

When the focus is to remedy some injustice by legal action, they are sometimes called "querulous paranoia".

In cases where reporters of stalking behavior have been judged to be making false reports, a majority of them were judged to be delusional.

Depersonalization is the third most common psychological symptom, after feelings of anxiety and feelings of depression. Depersonalization is a symptom of anxiety disorders, such as panic disorder. It can also accompany sleep deprivation (often occurring when suffering from jet lag), migraine, epilepsy (especially temporal lobe epilepsy), obsessive-compulsive disorder, stress, anxiety, and some cases of low latent inhibition. Interoceptive exposure is a non-pharmacological method that can be used to induce depersonalization.

A similar and overlapping concept called ipseity disturbance (ipse is Latin for "self" or "itself") may be part of the core process of schizophrenia spectrum disorders. However, specific to the schizophrenia spectrum seems to be "a "dis"location of first-person perspective such that self and other or self and world may seem to be non-distinguishable, or in which the individual self or field of consciousness takes on an inordinate significance in relation to the objective or intersubjective world" (emphasis in original).

For the purposes of evaluation and measurement depersonalisation can be conceived of as a construct and scales are now available to map its dimensions in time and space. A study of undergraduate students found that individuals high on the depersonalization/derealization subscale of the Dissociative Experiences Scale exhibited a more pronounced cortisol response. Individuals high on the absorption subscale, which measures a subject's experiences of concentration to the exclusion of awareness of other events, showed weaker cortisol responses.

A self-disorder, also called ipseity disturbance, is a psychological phenomenon of disruption or diminishing of a person's sense of minimal (or basic) self. The sense of minimal self refers to the very basic sense of having experiences that are one's own; it has no properties, unlike the more extended sense of self, the narrative self, which is characterized by the person's reflections on themselves as a person, things they like, their identity, and other aspects that are the result of reflection on one's self. Disturbances in the sense of minimal self, as measured by the Examination of Anomalous Self-Experience (EASE), aggregate in the schizophrenia spectrum disorders, to include schizotypal personality disorder, and distinguish them from other conditions such as psychotic bipolar disorder and borderline personality disorder.

311- Depressive Disorder Not Otherwise Specified (NOS)

The Depressive disorder NOS category includes disorders with depressive features that do not meet the criteria for Major Depressive Disorder, Dysthymic disorder, Adjustment Disorder with Depressed Mood or Adjustment Disorder with Mixed Anxiety and Depressed Mood. Sometimes depressive symptoms can present as part of an Anxiety Disorder Not otherwise Specified. Examples of Depressive Disorder Not Otherwise Specified include.

- Premenstrual Dysphoric Disorder: in most menstrual cycles during the past years, (e.g., markedly depressed mood, marked anxiety, marked affective lability, or decreased interest in activities) regularly occurred during the onset of menses. These symptoms must be severe enough to markedly interfere with work, school, or usual activities and be entirely absent for at least 1 week post menses.

- Minor depressive disorder: episodes of at least 2 weeks of depressive symptoms but with fewer than the five items required for Major Depressive Disorder.

- Recurrent brief depressive disorder: depressive episodes lasting from 2 days up to 2 weeks, occurring at least once a month for 12 months (not associated with the menstrual cycle)

- Post psychotic depressive Disorder of schizophrenia: a Major Depressive Episode that occurs during the residual phase of schizophrenia.

- A Major Depressive Episode superimposed on delusional disorder, Psychotic Disorder Not Otherwise Specified, or the active phase of schizophrenia.

- Situations in which the clinician has concluded that a depressive disorder is present but is unable to determine whether it is primary, due to a general medical condition, or substance induced.

Symptoms of the disorder may arise due to several reasons. These include:

- Distress due to medical conditions

- Environmental effects and situations

Post-schizophrenic depression is a "depressive episode arising in the aftermath of a schizophrenic illness where some low-level schizophrenic symptoms may still be present." Someone that suffers from post-schizophrenic depression experiences both symptoms of depression and can also continue showing mild symptoms of schizophrenia. Unfortunately, depression is a common symptom found in patients with schizophrenia and can fly under the radar for years before others become aware of its presence in a patient. However, very little research has been done on the subject, meaning there are few answers to how it should be systematically diagnosed, treated, or what course the illness will take. Some scientists would entirely deny the existence of post-schizophrenic depression, insisting it is a phase in schizophrenia as a whole. As of late, post-schizophrenic depression has become officially recognized as a syndrome and is considered a sub-type of schizophrenia.

Persecutory delusions are a set of delusional conditions in which the affected persons believe they are being persecuted. Specifically, they have been defined as containing two central elements:

1. The individual thinks that harm is occurring, or is going to occur.

2. The individual thinks that the perceived persecutor has the intention to cause harm.

According to the DSM-IV-TR, persecutory delusions are the most common form of delusions in paranoid schizophrenia, where the person believes "he or she is being tormented, followed, tricked, spied on, or ridiculed." They are also often seen in schizoaffective disorder and, as recognized by DSM-IV-TR, constitute the cardinal feature of the persecutory subtype of delusional disorder, by far the most common. Delusions of persecution may also appear in manic and mixed episodes of bipolar disease, polysubstance abuse, and severe depressive episodes with psychotic features, particularly when associated with bipolar illness.

The same criteria are used to diagnose children and adults. Diagnosis is based on reports by parents or caretakers, teachers, school officials, and others close to the child.

A professional who believes a child has schizophrenia usually conducts a series of tests to rule out other causes of behavior, and pinpoint a diagnosis. Three different types of exams are performed: physical, laboratory, and psychological. Physical exams usually cover the basic assessments, including but not limited to; height, weight, blood pressure, and checking all vital signs to make sure the child is healthy. Laboratory tests include electroencephalogram EEG screening and brain imaging scans. Blood tests are used to rule out alcohol or drug effects, and thyroid hormone levels are tested to rule out hyper- or hypothyroidism. A psychologist or psychiatrist talks to a child about their thoughts, feelings, and behavior patterns. They also inquire about the severity of the symptoms, and the effects they have on the child's daily life. They may also discuss thoughts of suicide or self-harm in these one-on-one sessions. Some symptoms that may be looked at are early language delays, early motor development delays and school problems.

Many of persons with childhood schizophrenia are initially misdiagnosed as having pervasive developmental disorders (autism spectrum disorder, for example).

Many patients who present with paraphrenia have significant auditory or visual loss, are socially isolated with a lack of social contact, do not have a permanent home, are unmarried and without children, and have maladaptive personality traits. While these factors do not cause paraphrenia, they do make individuals more likely to develop the disorder later in life.