Schizophrenia is a mental disorder that is characterized by at least 2 of the following symptoms, for at least one month:
- Disorganized speech (e.g., frequent derailment or incoherence)
- Grossly disorganized or catatonic behavior
- A set of three negative symptoms (a “flattening” of one’s emotions, alogia, avolition; see below)
Only one of the above symptoms is required to make the diagnosis of schizophrenia if the person’s delusions are bizarre or if the hallucinations consist of a voice keeping up a running commentary on the person’s behavior or thoughts, or two or more voices conversing with each other.
Although the above symptoms must be present for at least one (1) month, there also needs to be continuous signs of the disturbance that persist for at least six (6) months. During this period, the signs of the disorder may be present in a milder form, for instance as just odd beliefs or unusual perceptual experiences. During this 6 month period, at least two of the above criteria must be met, or only the criteria of Negative Symptoms must be present — if even just in milder form.
Onset of schizophrenia prior to adolescence is rare. The peak age at onset for the first psychotic episode is in the early- to mid-20s for males and in the late-20s for females. Though active symptoms typically do not emerge until an individual is in their 20′s, oftentimes prodromal symptoms will precede the first psychotic episode, characterized by milder forms of hallucinations or delusions. For example, individuals may express a variety of unusual or odd beliefs that are not of delusional proportions (e.g., ideas of reference or magical thinking); they may have unusual perceptual experiences (e.g., sensing the presence of an unseen person); their speech may be generally understandable but vague; and their behavior may be unusual but not grossly disorganized (e.g., mumbling in public).
Individuals with schizophrenia evidence large distress and impairments in various life domains. Functioning in areas such as work, interpersonal relations, or self-care must be markedly below the level achieved prior to the onset of the symptoms to receive the diagnosis (or when the onset is in childhood or adolescence, failure to achieve expected level of interpersonal, academic, or occupational achievement).
Schizoaffective Disorder and Mood Disorder With Psychotic Features must be considered as alternative explanations for the symptoms and have been ruled out. The disturbance must also not be due to the direct physiological effects of use or abuse of a substance (e.g., alcohol, drugs, medications) or a general medical condition.
If there is a history of Autistic Disorder or another Pervasive Developmental Disorder, the additional diagnosis of Schizophrenia is made only if prominent delusions or hallucinations are also present for at least a month (or less if successfully treated).
0.3%–0.7% of individuals appear to acquire schizophrenia. although there is reported variation by race/ethnicity, across countries, and by geographic origin for immigrants and children of immigrants. The sex ratio differs across samples and populationHostility and aggression can be associated with schizophrenia, although spontaneous or random assault is uncommon. Aggression is more frequent for younger males and for individuals with a past history of violence, non-adherence with treatment, substance abuse, and impulsivity. It should be noted that the vast majority of persons with schizophrenia are not aggressive and are more frequently victimized than are individuals in the general population.
Entry has been updated for DSM-5; diagnostic code 295.90.
Psych Central. (2014). Schizophrenia Symptoms. Psych Central. Retrieved on February 28, 2015, from http://psychcentral.com/disorders/schizophrenia-symptoms/
Symptom criteria summarized from:
American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders, fifth edition. Washington, DC: American Psychiatric Association.
American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders, fourth edition. Washington, DC: American Psychiatric Association.
Last reviewed: By John M. Grohol, Psy.D. on 22 Jun 2014
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