Diagnosis
Diagnosing schizophrenia is a complex process, as symptoms can vary among individuals.
In clinical practice and research settings, diagnostic classification systems are extensively utilized. These systems establish agreed sets of criteria used for defining and diagnosing illnesses.
Notable examples include:
the Diagnostic and Statistical Manual (DSM) published by the American Psychiatric Association and
the International Classification of Diseases (ICD) by the World Health Organization.
Both the DSM and ICD criteria are regularly revised, with the most recent versions being DSM-5 and ICD-11.
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To receive a DSM-5 diagnosis of schizophrenia, a minimum of two symptoms must be present for at least six months, with a significant portion occurring over a one-month period. Symptoms encompass delusions, hallucinations, disorganized speech and behavior, as well as negative symptoms such as reduced emotional expression, decreased speech, and lack of purposeful actions. At least one symptom of delusions, hallucinations, or disorganized speech is required, along with substantial impairment in social or occupational functioning.
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In the case of an ICD-11 diagnosis of schizophrenia, a minimum of two symptoms must be evident, which may include positive, negative, depressive, manic, psychomotor, and cognitive symptoms. Of these two symptoms, one must be a core symptom such as delusions, thought insertion, thought withdrawal, hallucinations, or thought disorder. Symptoms should have been present for the majority of the time over a period of at least one month.
The diagnosis may not be verified if you are continuously taking illicit drugs that may induce psychotic symptoms themself. This would be characterized as a drug-induced or drug-associated schizophrenia-like psychosis. However, if symptoms persist after substance use has been stopped and urine drug screening is negative for about 6 weeks, this needs to be reconsidered.