Fronto-striatal structures related with model-based control as an endophenotype for obsessive-compulsive disorder.

Area of Science:

• Neuroscience
• Psychiatry
• Computational Psychiatry

Background:

• Obsessive-compulsive disorder (OCD) is theorized to involve a shift from goal-directed to habitual decision-making.
• The heritability of this decision-making shift in OCD remains largely unexplored.

Purpose of the Study:

• To investigate the heritability of the shift towards model-free habitual control in obsessive-compulsive disorder (OCD).
• To examine differences in decision-making strategies between patients with OCD, unaffected siblings, and healthy controls.

Main Methods:

• Utilized the two-step task to assess decision-making in 32 OCD patients, 27 unaffected siblings (SIBs), and 31 healthy controls (HCs).
• Employed computational modeling to quantify the balance between model-based and model-free control.
• Conducted structural neuroimaging (80 subjects) and analyzed behavioral and reaction time data.

Main Results:

• A significant trend for increased model-free control was observed in the order OCD > SIB > HC.
• Reduced model-based control was evident in OCD patients compared to HCs and SIBs, with SIBs showing higher model-based control than HCs.
• Brain imaging revealed associations between decision-making effects and the surface area of the medial/right dorsolateral prefrontal cortex, as well as volumes of the putamen and caudate.

Conclusions:

• Findings suggest a potential heritable shift towards habitual decision-making in families with OCD.
• Reduced model-based control and its association with fronto-striatal structures may represent an endophenotype for OCD.