Gender, age and geographical representation over the past 50 years of schizophrenia research. (January 2022) - Alliende, Luz María
Highlights: We here examined changes in geographic location, gender and age of participants, in schizophrenia studies from a large database of over 3000 studies published in the last 50 years. We found that studies from low- and middle-income countries have been increasing since the 1990s, although are still under-represented when considering the size of the world's population they represent. Women have been historically under-represented in schizophrenia studies. This is less of a problem in low- and middle-income countries, such as China. Women's under-representation in studies has been improving significantly, and we could expect upper-income countries to reach representativeness within the next decade. There has not been any significant change in time in the mean age of participants. Abstract: Previous studies have suggested that subjects participating in schizophrenia research are not representative of the demographics of the global population of people with schizophrenia, particularly in terms of gender and geographical location. We here explored if this has evolved throughout the decades, examining changes in geographical location, gender and age of participants in studies of schizophrenia published in the last 50 years. We examined this using a meta-analytical approach on an existing database including over 3, 000 studies collated for another project. We found that the proportion of studies and participants from low-and-middle income countries has significantly increased over time, with considerable input from studies from China. However, it is still low when compared to the global population they represent. Women have been historically under-represented in studies, and still are in high-income countries. However, a significantly higher proportion of female participants have been included in studies over time. The age of participants included has not changed significantly over time. Overall, there have been improvements in the geographical and gender representation of people with schizophrenia. However, there is still a long way to go so research can be representative of the global population of people with schizophrenia, particularly in geographical terms.