Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany; and Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Germany
Heike Anderson-Schmidt
Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Germany
Monika Budde
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany
Ashley L. Comes
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany; and Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Germany; and International Max Planck Research School for Translational Psychiatry, Max Planck Institute of Psychiatry, Munich, Germany
Farahnaz Klöhn-Saghatolislam
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany; and Department of Immunology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
Sergi Papiol
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany; and Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Germany
Daniela Reich-Erkelenz
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany
Sabrina K. Schaupp
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany; and Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Germany
Fanny Senner
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany; and Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Germany
Thomas Vogl
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany
Jens Wiltfang
Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Germany; and German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany; and iBiMED, Medical Sciences Department, University of Aveiro, Aveiro, Portugal
Eva Reininghaus
Department of Psychiatry and Psychotherapeutic Medicine, Research Unit for Bipolar Affective Disorder, Medical University of Graz, Austria
Peter Falkai
Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Germany
Thomas G. Schulze
Institute of Psychiatric Phenomics and Genomics, University Hospital, LMU Munich, Germany; Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, NY, USA; and Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
Background Case-only longitudinal studies are common in psychiatry. Further, it is assumed that psychiatric ratings and questionnaire results of healthy controls stay stable over foreseeable time ranges. For cognitive tests, improvements over time are expected, but data for more than two administrations are scarce. Aims We comprehensively investigated the longitudinal course for trends over time in cognitive and symptom measurements for severe mental disorders. Assessments included the Trail Making Tests, verbal Digit Span tests, Global Assessment of Functioning, Inventory of Depressive Symptomatology, the Positive and Negative Syndrome Scale, and the Young Mania Rating Scale, among others. Method Using the data of control individuals (n = 326) from the PsyCourse study who had up to four assessments over 18 months, we modelled the course using linear mixed models or logistic regression. The slopes or odds ratios were estimated and adjusted for age and gender. We also assessed the robustness of these results using a longitudinal non-parametric test in a sensitivity analysis. Results Small effects were detected for most cognitive tests, indicating a performance improvement over time (P < 0.05). However, for most of the symptom rating scales and questionnaires, no effects were detected, in line with our initial hypothesis. Conclusions The slightly but consistently improved performance in the cognitive tests speaks of a test-unspecific positive trend, while psychiatric ratings and questionnaire results remain stable over the observed period. These detectable improvements need to be considered when interpreting longitudinal courses. We therefore recommend recruiting control participants if cognitive tests are administered.
