Does co-morbid obsessive-compulsive disorder modify the abnormal language processing in schizophrenia patients? An...

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Schizophrenia (SCH) is consistently linked to impaired language processing, evidenced by reduced activation in left prefrontal language areas (inferior frontal gyrus, IFG).
• This reduced language lateralization is observed in both chronic and first-episode SCH, suggesting it as a potential neurobiological marker.
• Previous research indicated this deficit is specific to SCH, as obsessive-compulsive disorder (OCD) patients show normal language processing.

Purpose of the Study:

• To investigate if co-occurring OCD in schizophrenia patients attenuates abnormal prefrontal language lateralization.
• To compare language processing and functional connectivity in patients with schizophrenia and comorbid OCD versus schizophrenia without OCD.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to assess regional activation and language lateralization in the IFG.
• Inter-hemispheric functional connectivity (FC) was examined during an auditory verb generation task.
• Participants included 14 SCH patients with OCD, 17 SCH patients without OCD, 13 OCD patients, and 14 healthy controls.

Main Results:

• Behavioral word generation performance did not differ between groups.
• OCD patients exhibited normal language lateralization, similar to healthy controls.
• Both schizophrenia groups (with and without OCD) showed reduced IFG lateralization and diminished inter-hemispheric FC compared to controls.

Conclusions:

• The presence of OCD does not mitigate the abnormal language processing observed in schizophrenia.
• These findings reinforce that language processing abnormalities are characteristic of schizophrenia.
• Combined schizophrenia-OCD psychopathology appears more aligned with schizophrenia than with OCD in terms of language processing deficits.