Cognitive Trajectories over 13 Years in Schizophrenia Spectrum Disorders: Addressing Selective Dropout Bias.
9 affiliations
- 1Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, 171 77, Stockholm, Sweden.
- 2Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77, Stockholm, Sweden.
- 3Department of Psychiatry and Behavioral Sciences, Stanford School of Medicine, Stanford, CA 94305-5717, United States.
- 4Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, United States.
- 5Department of Clinical Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
- 6Department of Psychiatric Research, Diakonhjemmet Hospital, 0319 Oslo, Norway.
- 7Centre of Precision Medicine, Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway.
- 8VA Palo Alto Health Care System, Palo Alto, CA 94304-1207, United States.
- 9Institute of Clinical Medicine, Division of Mental Health and Addiction, University of Oslo, 0424 Oslo, Norway.
Abstract
Background and hypothesis
The longitudinal course of cognitive functioning in schizophrenia is debated. Previous longitudinal studies have reported selective attrition. We aimed to analyze cognitive trajectories over 13 years among patients with schizophrenia spectrum disorders (SSDs) in comparison with controls, while accounting for dropout bias, and explored baseline predictors of cognitive outcome.Study design
Cognition was assessed at study start, 5-year, and 13-year follow-up in 108 participants with schizophrenia spectrum disorder and 85 controls of similar age. Linear Mixed Effects models were used to model trajectories over time, with inverse probability weights to account for non-random dropout in patients. Predictors of cognitive function at 13 years were explored using linear regression.Study results
Retention was 51% for patients and 65% for controls. At study start, patients who dropped out performed worse on most cognitive tasks and were significantly older (4.5 years) than completers. In primary inverse probability of attrition weight-weighted analyses, patients scored lower than controls across nearly all cognitive domains (cognitive composite: β = -0.91 SD [95% CI -1.42, -0.39]) but their trajectories did not significantly differ from those of controls. Higher age predicted worse cognitive function. Illness duration was an independent negative predictor in patients. Study start cognition predicted 13-year follow-up cognition in patients.Conclusions
Although cognitive performance of patients was lower than that of controls at study start, their change in performance over 13 years did not differ from the controls. Patients who dropped out were more cognitively impaired, highlighting risk of attrition bias. The robustness of findings across weighted and unweighted analyses strengthens confidence in the observed trajectories.
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BibTeX
@article{lee2026cognitive,
title = {{Cognitive Trajectories over 13 Years in Schizophrenia Spectrum Disorders: Addressing Selective Dropout Bias.}},
author = {Maria Lee and Granville J Matheson and Ellen E Lee and Sara Holmqvist and Håkan Nyman and Ingrid Agartz and Alison R Hwong and Erik G Jönsson},
journal = {Schizophrenia bulletin},
year = {2026},
month = oct,
doi = {10.1093/schbul/sbag162},
url = {https://europepmc.org/article/MED/42960989},
note = {CC BY},
}
RIS
TY - JOUR
TI - Cognitive Trajectories over 13 Years in Schizophrenia Spectrum Disorders: Addressing Selective Dropout Bias.
AU - Maria Lee
AU - Granville J Matheson
AU - Ellen E Lee
AU - Sara Holmqvist
AU - Håkan Nyman
AU - Ingrid Agartz
AU - Alison R Hwong
AU - Erik G Jönsson
PY - 2026
DA - 2026/10/01
JO - Schizophrenia bulletin
DO - 10.1093/schbul/sbag162
UR - https://europepmc.org/article/MED/42960989
AB - Background and hypothesis The longitudinal course of cognitive functioning in schizophrenia is debated. Previous longitudinal studies have reported selective attrition. We aimed to analyze cognitive trajectories over 13 years among patients with schizophrenia spectrum disorders (SSDs) in comparison with controls, while accounting for dropout bias, and explored baseline predictors of cognitive outcome.Study design Cognition was assessed at study start, 5-year, and 13-year follow-up in 108 participants with schizophrenia spectrum disorder and 85 controls of similar age. Linear Mixed Effects models were used to model trajectories over time, with inverse probability weights to account for non-random dropout in patients. Predictors of cognitive function at 13 years were explored using linear regression.Study results Retention was 51% for patients and 65% for controls. At study start, patients who dropped out performed worse on most cognitive tasks and were significantly older (4.5 years) than completers. In primary inverse probability of attrition weight-weighted analyses, patients scored lower than controls across nearly all cognitive domains (cognitive composite: β = -0.91 SD [95% CI -1.42, -0.39]) but their trajectories did not significantly differ from those of controls. Higher age predicted worse cognitive function. Illness duration was an independent negative predictor in patients. Study start cognition predicted 13-year follow-up cognition in patients.Conclusions Although cognitive performance of patients was lower than that of controls at study start, their change in performance over 13 years did not differ from the controls. Patients who dropped out were more cognitively impaired, highlighting risk of attrition bias. The robustness of findings across weighted and unweighted analyses strengthens confidence in the observed trajectories.
SN - 1787-9965
SN - 1745-1701
SN - 0586-7614
ER -