Severity in the chapter “Assessment Measures.”)
Note:  Diagnosis of schizophrenia can be made without using this severity specifier.
Diagnostic Features 
The characteristic symptoms of schizophrenia involve a range of cogn itive, behavioral, and
emotional dysfunctions, but no single sympto m is pathognomonic of the disorder. The di-
agnosis involves the recognition of a constellation of sign s and symptoms associated with
impaired occupational or social functioning. Individuals with the disorder will vary sub-
stantially on most features, as schizophrenia is a heterogeneous clinical syndrome.
At least two Criterion A symptoms must be  present for a significant portion of time
during a 1-month period or longer. At least one of these symptoms must be the clear pres-
ence of delusions (Criterion A1), hallucinati ons (Criterion A2), or disorganized speech
(Criterion A3). Grossly disorganized or ca tatonic behavior (Criterion A4) and negative
symptoms (Criterion A5) may also be present.  In those situations in which the active-
phase symptoms remit within a mo nth in response to treatment, Criterion A is still met if the
clinician estimates that they would have persisted in the absence of treatment. 
Schizophrenia involves impairment in one or more major areas of functioning (Crite-
rion B). If the disturbance begins in childhood or adolescence,  the expected level of func-
tion is not attained. Co mparing the individual with unaffected siblings may be helpful. The
dysfunction persists for a substantial period du ring the course of the disorder and does not
appear to be a direct result of any single feature. Avolition (i.e., reduced drive to pursue
goal-directed behavior; Criterion A5) is linked to the social dysfunction described under
Criterion B. There is also strong evidence for a relationship betw een cognitive impairment