Since the diagnostic criteria for schizophreniform disorder and schizophrenia differ primarily in duration of illness, the discussion of the differential diagnosis of schizophre- nia also applies to schizophreniform disorder.
Brief psychotic disorder. Schizophreniform disorder differs in duration from brief psy- chotic disorder, which has a duration of less than 1 month.
Diagnostic Criteria 295.90 (F20.9)
A. Two (or more) of the following, each present for a significant portion of time during a 1-month period (or less it successfully treated). At least one of these must be (1 ), (2), or (3): 1. Delusions.
Hallucinations.
Disorganized speech (e.g., frequent derailment or incoherence).
Grossly disorganized or catatonic behavior.
Negative symptoms (i.e., diminished emotional expression or avolition).
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B. For a significant portion of the time since the onset of the disturbance, level of function- ing in one or more major areas, such as work, interpersonal relations, or self-care, is markedly below the level achieved prior to the onset (or when the onset is in childhood or adolescence, there is failure to achieve expected level of interpersonal, academic, or occupational functioning).
C. Continuous signs of the disturbance persist for at least 6 months. This 6-month period must include at least 1 month of symptoms (or less it successfully treated) that meet Cri- terion A (i.e., active-phase symptoms) and may include periods of prodromal or residual symptoms. During these prodromal or residual periods, the signs of the disturbance may
A present in an attenuated form (e.g., odd beliefs, unusual perceptual experiences).
D. Schizoaffective disorder and depressive or bipolar disorder with psychotic features have been ruled out because either 1) no major depressive or manic episodes have occurred concurrently with the active-phase symptoms, or 2) if mood episodes have occurred during active-phase symptoms, they have been present for a minority of the total duration of the active and residual periods of the illness.
E. The disturbance is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication) or another medical condition.
F. If there is a history of autism spectrum disorder or a communication disorder of child- hood onset, the additional diagnosis of schizophrenia is made only if prominent delu- sions or hallucinations, in addition to the other required symptoms of schizophrenia, are also present for at least 1 month (or less if successfully treated).
Specify if:
The following course specifiers are only to be used after a 1-year duration of the disorder and if they are not in contradiction to the diagnostic course criteria.
First episode, currently in acute episode: First manifestation of the disorder meet- ing the defining diagnostic symptom and time criteria. An acute episode is a time pe- riod in which the symptom criteria are fulfilled.
First episode, currently in partial remission: Partial remission is a period of time during which an improvement after a previous episode is maintained and in which the defining criteria of the disorder are only partially fulfilled.
First episode, currently in full remission: Full remission is a period of time after a previous episode during which no disorder-specific symptoms are present.
Multiple episodes, currently in acute episode: Multiple episodes may be deter- mined after a minimum of two episodes (i.e., after a first episode, a remission and a minimum of one relapse).
Multiple episodes, currently in partial remission
Multiple episodes, currently in full remission
Continuous: Symptoms fulfilling the diagnostic symptom criteria of the disorder are remaining for the majority of the illness course, with subthreshold symptom periods be- ing very brief relative to the overall course.
Specify if:
With catatonia (refer to the criteria for catatonia associated with another mental disorder, pp. 119—120, for definition).