Aim: To investigate the gender ratios (i.e. how many males, how many females took part per study) present in research studies on schizophrenia.
Participants: A total of 252,578 participants (147,725 male; 104, 853 female = 66% male; 34% female) amassed from 220 articles taken from a range of psychological journals.
Procedure: A review article in which a range of studies were analysed by the researchers to look for inconsistencies in terms of the number of males and females who featured as participants.
Results: The findings included the following observations:
- One meta-analysis that the researchers reviewed showed that the number of males used in schizophrenia is almost double that of the number of females used (1.94 males for every female participant)
- Males outnumbered females across all of the studies reviewed
- Males develop schizophrenia at an earlier age than females so this may be one reason for the gender imbalance in research
- Females who developed schizophrenia after the age of 45 were excluded from some early research which has resulted in this diagnostic bias towards males
- Females may be under-used as participants in studies of schizophrenia which means that the findings and conclusions of schizophrenia research may over-represent the male experience and under-represent the female experience
Conclusion: Females presenting with schizophrenic symptoms may be misdiagnosed due to clinicians operating a gender bias based on under-representation of females in research studies.