Criteria<unk>  is diagnosed based on criteria in either the Diagnostic and Statistical Manual of Mental Disorders (DSM) published by the American Psychiatric Association or the International Statistical Classification of Diseases and Related Health Problems (ICD) published by the World Health Organization (WHO). These criteria use the self-reported experiences of the person and reported abnormalities in behavior, followed by a psychiatric assessment. The mental status examination is an important part of the assessment. An established tool for assessing the severity of positive and negative symptoms is the Positive and Negative Syndrome<unk> ale (PANSS). This has been seen to have shortcomings relating to negative symptoms, and other<unk> ales – the Clinical Assessment Interview for Negative Symptoms (CAINS), and the Brief Negative Symptoms<unk> ale (BNSS) have been introduced. The DSM-5, published in 2013, gives a<unk> ale to Assess the Severity of Symptom Dimensions outlining eight dimensions of symptoms. DSM-5 states that to be diagnosed with<unk> , two diagnostic criteria have to be met over the period of one month, with a significant impact on social or occupational functioning for at least six months. One of the symptoms needs to be either delusions, hallucinations, or disorganized speech. A second symptom could be one of the negative symptoms, or severely disorganized or catatonic behaviour. A different diagnosis of<unk> orm disorder can be made before the six months needed for the diagnosis of<unk> . In Australia the guideline for diagnosis is for six months or more with symptoms severe enough to affect ordinary functioning. In the UK diagnosis is based on having the symptoms for most of the time for one month, with symptoms that significantly affect the ability to work, study, or to carry on ordinary daily living, and with other similar conditions ruled out. The ICD criteria are typically used in European countries; the DSM criteria are used predominantly in the United States and Canada, and are prevailing in research studies. In practice, agreement between the two systems is high. The current proposal for the ICD-11 criteria for<unk>  recommends adding self-disorder as a symptom. A major unresolved difference between the two diagnostic systems is that of the requirement in DSM of an impaired functional outcome. WHO for ICD argues that not all people with<unk>  have functional deficits and so these are not specific for the diagnosis. Changes made Both manuals have adopted the chapter heading of<unk>  spectrum and other psychotic disorders; ICD modifying this as<unk>  spectrum and other primary psychotic disorders. The definition of<unk>  remains essentially the same as that specified by the 2000 text revised DSM-IV (DSM-IV-TR). However, with the publication of DSM-5, the APA removed all sub-classifications of<unk> . ICD-11 has also removed subtypes. The removed subtype from both, of catatonic has been relisted in ICD-11 as a psychomotor disturbance that may be present in<unk> . Another major change was to remove the importance previously given to<unk> neider's first-rank symptoms. DSM-5 still uses the listing of<unk> orm disorder but ICD-11 no longer includes it. DSM-5 also recommends that a better distinction be made between a current condition of<unk>  and its historical progress, to achieve a clearer overall characterization. A dimensional assessment has been included in DSM-5 covering eight dimensions of symptoms to be rated (using the<unk> ale to Assess the Severity of Symptom Dimensions) – these include the five diagnostic criteria plus cognitive impairments, mania, and depression. This can add relevant information for the individual in regard to treatment, prognosis, and functional outcome; it also enables the response to treatment to be more accurately described. Two of the negative symptoms – avolition and diminished emotional expression – have been given more prominence in both manuals. Comorbidities Many people with<unk>  may have one or more other mental disorders, such as panic disorder, obsessive–compulsive disorder, or substance use disorder. These are separate disorders that require treatment. When comorbid with<unk> , substance use disorder and antisocial personality disorder both increase the risk for violence. Comorbid substance use disorder also increases risk for suicide. Sleep disorders often co-occur with<unk> , and may be an early sign of relapse. Sleep disorders are linked with positive symptoms such as disorganized thinking and can adversely affect cortical plasticity and cognition. The consolidation of memories is disrupted in sleep disorders. They are associated with severity of illness, a poor prognosis, and poor quality of life. Sleep onset and maintenance insomnia is a common symptom, regardless of whether treatment has been received or not. Genetic variations have been found associated with these conditions involving the circadian rhythm, dopamine and histamine metabolism, and signal transduction. Limited positive evidence has been found for the use of acupuncture as an add-on. Differential diagnosis To make a diagnosis of<unk>  other possible causes of psychosis need to be excluded. Psychotic symptoms lasting less than a month may be diagnosed as brief psychotic disorder, or as<unk> orm disorder. Psychosis is noted in Other specified<unk>  spectrum and other psychotic disorders as a DSM-5 category.<unk> izoaffective disorder is diagnosed if symptoms of mood disorder are substantially present alongside psychotic symptoms. Psychosis that results from a general medical condition or substance is termed secondary psychosis. Psychotic symptoms may be present in several other conditions, including bipolar disorder, borderline personality disorder, substance intoxication, substance-induced psychosis, and a number of drug withdrawal syndromes. Non-bizarre delusions are also present in delusional disorder, and social withdrawal in social anxiety disorder, avoidant personality disorder and<unk> izotypal personality disorder.<unk> izotypal personality disorder has symptoms that are similar but less severe than those of<unk> .<unk>  occurs along with obsessive–compulsive disorder (OCD) considerably more often than could be explained by chance, although it can be difficult to distinguish obsessions that occur in OCD from the delusions of<unk> . There can be considerable overlap with the symptoms of post-traumatic stress disorder. A more general medical and neurological examination may be needed to rule out medical illnesses which may rarely produce psychotic<unk> -like symptoms, such as metabolic disturbance, systemic infection, syphilis, HIV-associated neurocognitive disorder, epilepsy, limbic encephalitis, and brain lesions. Stroke, multiple<unk> lerosis, hyperthyroidism, hypothyroidism, and dementias such as Alzheimer's disease, Huntington's disease, frontotemporal dementia, and the Lewy body dementias may also be associated with<unk> -like psychotic symptoms. It may be necessary to rule out a delirium, which can be distinguished by visual hallucinations, acute onset and fluctuating level of consciousness, and indicates an underlying medical illness. Investigations are not generally repeated for relapse unless there is a specific medical indication or possible adverse effects from antipsychotic medication. In children hallucinations must be separated from typical childhood fantasies. It is difficult to distinguish childhood<unk>  from autism.
Schizophrenia
Delusional disorder
Disorganized schizophrenia
Schizoaffective disorder
Simple-type schizophrenia
Autism
Schizophreniform disorder
Bipolar disorder