An association between deficit schizophrenia and male gender could be expec
ted, since male schizophrenic subjects have been repeatedly found more seve
re than females on several dimensions of severity. Surprisingly, very few s
tudies have confirmed such an association. We performed a more definitive t
est of this association using a meta-analysis. A pooled odds ratio was comp
uted based on the 23 studies that reported the gender ratio in deficit vs,
non-deficit schizophrenia. We tested for the heterogeneity of the associati
on and examined the potential impact of the sampling method, the method use
d to assess the deficit syndrome, the breadth of diagnoses included and the
mean duration of illness. A highly significant association between male ge
nder and deficit schizophrenia was observed (pooled odds ratio = 1.75). The
re was no definitive evidence that differences across studies in sampling m
ethods, breadth of diagnoses included, mean duration of illness and methods
to assess the deficit syndrome affected the strength of the association. H
owever, the studies using the 'Proxy Deficit Syndrome' method to assess the
deficit syndrome yielded qualitatively weaker evidence. This significant a
ssociation between male gender and deficit schizophrenia may reflect the in
fluence of a gender related factor (e.g. sexual hormones) or gender differe
nces in the liability to different etiologies of schizophrenia. The role of
gender as a potential confounder must be closely examined in studies compa
ring deficit and non-deficit SZ. (C) 2001 Elsevier Science B.V. All rights
reserved.