Fañanas L, Marti-Tusquets J L, Bertranpetit J
Soc Psychiatry Psychiatr Epidemiol. 1989 Sep;24(5):266-70. doi: 10.1007/BF01788969.
The seasonality of birth in 142 schizophrenics from Barcelona (Spain) has been studied, showing a pattern similar to that described by other authors, with a maximum in winter. If sample is compared with the local general population there are significant differences, but these disappear when the comparison is made with a control population properly stratified by age, sex, place of birth, place of residence and social status. The same results are obtained using statistical methods suggested by other authors. The seasonality pattern usually obtained in schizophrenia could be due to a selective stratification of the ill population based on variables that might or might not be related to illness.
对来自西班牙巴塞罗那的142名精神分裂症患者的出生季节性进行了研究，结果显示出与其他作者所描述的模式相似，冬季出生人数最多。如果将该样本与当地普通人群进行比较，会存在显著差异，但当与按年龄、性别、出生地、居住地和社会地位进行适当分层的对照人群进行比较时，这些差异就消失了。使用其他作者提出的统计方法也得到了相同的结果。精神分裂症中通常观察到的季节性模式可能是由于患病群体基于可能与疾病相关或不相关的变量进行了选择性分层。
