Attrition in longitudinal studies among patients with schizophrenia and other psychoses; findings from the STRATA collaboration

L.E Homman,S.E Smart,F O'Neill,J.H Maccabe

doi:10.1016/j.psychres.2021.114211

L.E Homman, S.E Smart + Show 2 more

Open Access

https://doi.org/10.1016/j.psychres.2021.114211

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Abstract

A major problem with longitudinal studies is the bias generated due to attrition, particularly apparent amongst patients suffering from psychotic disorders. Factors associated with study-participation were investigated as part of a larger research collaboration (STRATA). Out of 479 eligible participants, only 50 (10,4%) were successfully followed up. The present study investigated whether study participation differed depending on baseline characteristics. Results indicated that individuals who did not participate were more likely to report an alcohol use disorder while those who did respond were more likely to have been in full-time education for longer and be of white ethnicity. Participation did not differ depending on diagnosis, symptoms, GAF, age of onset or depression.

Highlights

Longitudinal studies, where participants are followed up over many years and provide data at multiple time points, contribute valuable in formation to our understanding of disease trajectories and prognosis prediction
It is rare that all participants continue until the end of longitudinal studies, in mental health research and research involving patients with psychosis and schizophrenia
A total of 479 participants were eligible for STRATA, 183 females and 296 males

Summary

Introduction

Longitudinal studies, where participants are followed up over many years and provide data at multiple time points, contribute valuable in formation to our understanding of disease trajectories and prognosis prediction. They overcome many of the limitations of case-control studies and allow researchers to draw stronger conclusions on the di rection of causal relationships. It is rare that all participants continue until the end of longitudinal studies, in mental health research and research involving patients with psychosis and schizophrenia This attrition can reduce the power of a study, violate assumptions required for statistical analysis, and bias results. Clinicians and researchers can benefit from identifying the differ ences between patients who complete longitudinal studies and those who do not, by applying this knowledge to both the design of longitu dinal studies and recruitment strategies

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