A longitudinal approach to biological psychiatric research: The PsyCourse study

Abstract

In current diagnostic systems, schizophrenia and bipolar disorder are still conceptualized as distinct categorical entities. Recently, both clinical and genomic evidence have challenged this Kraepelinian dichotomy. There are only few longitudinal studies addressing potential overlaps between these conditions. Here, we present design and first results of the PsyCourse study (N = 891 individuals at baseline), an ongoing transdiagnostic study of the affective-to-psychotic continuum that combines longitudinal deep phenotyping and dimensional assessment of psychopathology with an extensive collection of biomaterial. To provide an initial characterization of the PsyCourse study sample, we compare two broad diagnostic groups defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) classification system, that is, predominantly affective (n = 367 individuals) versus predominantly psychotic disorders (n = 524 individuals). Depressive, manic, and psychotic symptoms as well as global functioning over time were contrasted using linear mixed models. Furthermore, we explored the effects of polygenic risk scores for schizophrenia on diagnostic group membership and addressed their effects on nonparticipation in follow-up visits. While phenotypic results confirmed expected differences in current psychotic symptoms and global functioning, both manic and depressive symptoms did not vary between both groups after correction for multiple testing. Polygenic risk scores for schizophrenia significantly explained part of the variability of diagnostic group. The PsyCourse study presents a unique resource to research the complex relationships of psychopathology and biology in severe mental disorders not confined to traditional diagnostic boundaries and is open for collaborations.

The genetic relationship between educational attainment and cognitive performance in major psychiatric disorders

“…Data were used from the multicenter, PsyCourse study in Germany and Austria, consisting of participants of European ancestry (www.PsyCourse.de) 31 . Participants were phenotyped using a comprehensive battery including data on socio-demographics, psychopathology, cognition, and functioning assessed at each of four visits (6-month intervals).…”

“…However, limited evidence exists supporting this association in patients with known cognitive deficits 29,30 , and there remains a need to investigate this association across different cognitive domains. Here we analyzed whether GPS EDU could be used to explain variability in different cognitive domains in chronic patients with schizophrenia and bipolar disorder from the PsyCourse cohort 31 . This transdiagnostic approach aligns with the growing evidence for dimensional models that cut across diagnostic categories in psychiatry and is supported by the large cognitive, clinical and genetic overlaps between both disorders 32,33 .…”

Overdispersed gene expression in schizophrenia

“…People with the disorder vary widely in their symptoms, course of illness, and treatment response 4 . A reliable clinical typology of SCZ has proved difficult to develop [5][6][7] . Assessment of clinical outcomes in SCZ is challenging 8,9 .…”

The PsyCourse Infrastructure as an Example for Longitudinal Research in Biological Psychiatry

“…Properties of the PsyCourse study: Founded originally under the name "Klinische Forschergruppe 241" in 2011, PsyCourse is an observational longitudinal multi-center (19 centers) study conducted in Germany and Austria (Budde et al, 2019). For the Psy-Course study, both clinical (patients) and nonclinical (controls) participants are recruited.…”