Birth Seasonality and Schizophrenia

To the Editor.—  We were intrigued by the findings of Watson et al¹ regarding schizophrenic birth seasonality, particularly their suggestion that an increase in the number of winter births is demonstrable in schizophrenics with severe process disorder but not in schizophrenics with good prognoses and reactive syndromes. We have arrived at a parallel finding from a different direction, in which we examined the hypothesis, advanced by Andreasen and Olsen,² that schizophrenics with positive syndromes (eg, a predominance of florid symptoms such as thought disorder, hallucinations, and delusions) and schizophrenics with negative syndromes (eg, a predominance of symptoms such as impoverished speech and thinking, affective flattening, avolition, and anhedonia) represent distinct subtypes. When comparing groups of well-characterized schizophrenics who met our criteria for a positive v negative syndrome, we reported³ that the patients with negative syndromes displayed more primitive cognitive modes on developmental tests and greater psychomotor retardation, despite equivalent