ORIGINAL ARTICLE Season of birth, gender and negative symptoms in schizophrenia A. Troisi 1 *, A. Pasini 1 , G. Spalletta 2 1 Department of Psychiatry, University of Rome Tor Vergata, Rome, Italy; 2 IRCCS Santa Lucia, Rome, Italy (Received 15 September 2000; revised 7 June 2001; accepted 22 July 2001) Summary – The aim of this study was to ascertain whether the symptom profile distinguishes between schizophrenic patients born in the winter and early spring and those born in other seasons. The sample consisted of 204 patients with a DSM-III-R diagnosis of schizophrenia who had been hospitalized for acute psychotic decompensation. Symptom ratings were based on the Positive and Negative Syndrome Scale (PANSS). The use of demographic and anamnestic data as dependent variables did not detect any season-of-birth effect. In contrast, clear gender-specific differences emerged from the comparison focusing on symptom dimensions and clinical subtype. Female patients born in the winter and early spring had higher scores on the PANSS negative scale and anergia factor whereas male patients born in other seasons had higher scores on the PANSS anergia factor. In addition, we found a gender-specific association between season of birth and clinical subtype. Most paranoid female patients were born in the non-winter months whereas, among men, a slightly higher percentage of paranoid patients were born in winter months. These results suggest that gender plays a role in modulating the effect of the season of birth on symptoms of schizophrenia. © 2001 Éditions scientifiques et médicales Elsevier SAS gender / negative symptoms / schizophrenia / season of birth INTRODUCTION One of the most consistently replicated findings in schizophrenia research is that, throughout the temper- ate latitudes of the northern hemisphere, patients diag- nosed as schizophrenic are more often born in the winter and early spring [2, 3, 36]. Kendell and Kemp [16] suggested that if some agent making a contribu- tion to the etiology of schizophrenia acts only, or mainly, in the winter and early spring months, there might be differences between the schizophrenic ill- nesses to which this seasonal agent had and had not contributed. If so, there might be detectable clinical differences between patients born in the season of excess risk and those born during the rest of the year. Based on this hypothesis, many studies have com- pared winter- and non-winter-born schizophrenic patients on a variety of variables including gender [1, 11, 28], place of birth (i.e., urban vs rural) [24], family history of mental disorder [7, 25], electrodermal activ- ity [14], ventricular enlargement [9, 32], neuropsycho- logical impairment [12], clinical subtype [10, 13, 18], and symptom profile [8, 20, 26, 31]. The primary goal of this study was to ascertain whether the symptom profile (as assessed by a dimen- sional instrument specifically designed for evaluating *Correspondence and reprints: Cattedra di Psichiatria, Università di Roma Tor Vergata, via G.A. Guattani 14, 00161 Rome, Italy. E-mail address: alfonso.troisi@uniroma2.it (A. Troisi). Eur Psychiatry 2001 ; 16 : 342-8 © 2001 Éditions scientifiques et médicales Elsevier SAS. All rights reserved S0924933801005892/FLA