Investigating disorder-specific and transdiagnostic alterations in model-based and model-free decision-making Article Swipe
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· 2024
· Open Access
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· DOI: https://doi.org/10.1503/jpn.240020
· OA: W4404634057
Background Decision-making alterations are present in psychiatric illnesses like major depressive disorder (MDD), obsessive–compulsive disorder (OCD), and schizophrenia, linked to symptoms of the respective disorders. We sought to analyze unique and shared decision-making alterations in these disorders, which is crucial for early diagnosis and treatment, especially given potential comorbidities. Methods Using 2 computational modelling approaches — logistic regression and hierarchical Bayesian modelling — we analyzed alterations in model-based and model-free decision-making in a transdiagnostic cohort of patients with MDD, OCD, or schizophrenia. Our aim was to identify disorder-specific and shared alterations and their associations with symptoms. Results We included 23 patients with MDD, 25 patients with OCD, 27 patients with schizophrenia, and 25 controls. Overall, participants of all groups relied on model-free decision-making. Patients with schizophrenia had the lowest learning rate and highest switching rate, indicating low perseverance. Furthermore, patients with OCD were more random in both task stages than controls and patients with MDD. All patient groups exhibited more randomness in responses than controls, with the schizophrenia group showing the highest levels. Increased model-free behaviour correlated with elevated depressive symptoms, and more model-based decision-making was linked to lower anhedonia levels across all patient groups. Limitations The sample size in each group was small. Conclusion This study highlights disorder-specific and shared decision-making alterations among people with MDD, OCD, or schizophrenia. Our findings suggest that anhedonia and depressive symptoms, which are present in all 3 disorders, share underlying behavioural mechanisms. Improving model-based behaviour may be a target for intervention and treatment. Furthermore, completely random behaviour in the 2-step task appears to distinctly differentiate patients with schizophrenia in remission.
