Working memory dysfunction in schizophrenia patients with obsessive-compulsive symptoms: an fMRI study.

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• A significant portion of schizophrenia patients also meet criteria for obsessive-compulsive disorder (OCD).
• Patients with both schizophrenia and OCD (schizo-obsessive) present unique clinical features, treatment responses, and prognoses.
• Distinct brain activation patterns in schizo-obsessive patients remain largely unexplored.

Purpose of the Study:

• To investigate whether patients with schizophrenia and comorbid OCD exhibit different brain activation and functional connectivity (FC) patterns during a working memory (WM) task compared to schizophrenia patients without OCD.
• To identify potential neurobiological differences in the schizo-obsessive subgroup.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed during an N-back working memory task.
• Three groups were studied: schizo-obsessive (n=16), schizophrenia (n=17), and matched healthy volunteers (n=20).
• Analysis focused on working memory-related activation in the right dorsolateral prefrontal cortex (DLPFC) and right caudate nucleus, along with functional connectivity (FC).

Main Results:

• Both schizophrenia groups (with and without OCD) demonstrated reduced activation in the right DLPFC and right caudate nucleus compared to healthy controls.
• Decreased functional connectivity was observed in both schizophrenia groups relative to healthy individuals.
• The severity of schizophrenic or OCD symptoms did not correlate with the observed reductions in regional brain activation.

Conclusions:

• Schizo-obsessive patients do not exhibit distinct brain activation patterns compared to schizophrenia patients without OCD during the N-back working memory task.
• Future research should explore cognitive paradigms targeting alternative neural networks, such as the orbitofrontal cortex, to uncover potential unique brain activation patterns in the schizo-obsessive subgroup.