Differential effects of amphetamine and neuroleptics on negative vs. positive symptoms in schizophrenia.

Positive symptoms of schizophrenia were diminished by neuroleptics and increased by amphetamine and accounted for most of the change seen in the total Brief Psychiatric Rating Scale (BPRS). Negative symptoms in the same subjects were not affected by neuroleptics but increased after amphetamines to a degree that just attained statistical significance. This increase was due to one item (emotional withdrawal) of the negative symptom factor which responded to neuroleptics and amphetamines as did positive symptoms. These findings are discussed with respect to new ideas about the role of dopamine in schizophrenia.