Diagnosis and six-month stability of negative symptoms in psychotic disorders.

Negative symptoms were examined in 150 primarily first-admission patients diagnosed with schizophrenia, schizoaffective disorder, psychotic depression, psychotic bipolar disorder, and 'other' psychoses. The analysis focused on patients who were rated on the Scale for the Assessment of Negative Symptoms (SANS) within 45 days of admission and at follow-up 6 months later. Significantly more schizophrenics had moderate to severe negative symptoms at each time point compared with other psychotic patients. The SANS scores were found to be relatively stable over time in all five diagnostic groups. Although the DSM-IV includes alogia, affective flattening, and avolition in the A criterion for schizophrenia, only alogia and affective flattening were found to be specific to this disorder. Our results point to the existence and enduring quality of negative symptoms in the early phase of psychosis and its specificity to schizophrenia even at this early stage.