Influence of diagnostic classification on gender ratio in schizophrenia

Background The research literature on hospital admissions for psychoses in youths was reviewed in order to test whether there was a gender ratio discrepancy in diagnostic subgroups; the effect of the diagnostic criteria classification on this measure was also investigated. Method A meta-analysis was conducted on 12 primary studies by assessing the male/female odds ratio (OR) in the schizophrenia and mood disorders with psychosis subgroups as well as the amount of variability between studies.Study inclusion criteria were: patients between the ages of 8 and 19, at least 15 patients with psychosis and a standardized diagnostic criteria classification system such as DSM, ICD or RDC. Results The male/female OR measured in this meta-analysis implies that a male subject with psychosis is 1.7 times as likely to obtain a diagnosis of schizophrenia; conversely, a female subject with psychosis is 2.1 times as likely to be assigned in the mood disorders with psychosis subgroup.Disparity in diagnostic criteria nomenclature (ICD-9 vs.DSM) could account for a statistically significant difference in male/female OR for the schizophrenia subgroup in a subset of 11 studies. Conclusions Under the narrower definition of schizophrenia in studies using DSM diagnostic criteria classification, the shift towards a greater proportion of patients diagnosed with mood disorders with psychosis could be explained by the time criteria; the simultaneous emergence of the gender ratio difference is discussed. This study shows that subtle changes in diagnostic criteria in psychiatric illnesses can greatly influence observational data pertaining to youths