Psychiatry Investig.  2009 Dec;6(4):286-293.

Comparative Analysis of Cognitive Function in Schizophrenia with and without Obsessive Compulsive Disorder

• Lee MJ
• Shin YB
• Sunwoo YK
• Jung SH
• Kim WH
• Kang MH
• Lee JS
• Bae JN
• Kim CE

Abstract

OBJECTIVE
We investigated the neurocognitive deficits in schizophrenic patients with and without obsessive-compulsive disorder (OCD). METHODS: We grouped 27 patients as either obsessive-compulsive or non-obsessive-compulsive based on the presence of OCD. The two groups completed the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), Positive and Negative Symptom Scale (PANSS), and Hamilton Depression Scale. The intelligence quotient (IQ) was tested using the Korean Wechsler Adult Intelligence Scale. The memory quotient (MQ) was tested using the Korean-Auditory Verbal Learning and Korean-Complex Figure Test. The executive intelligence quotient (EIQ) was determined using the Kims executive intelligence test (EXIT). RESULTS: Ten of the 27 patients had OCD. The compulsion score of Y-BOCS was positively correlated with positive symptoms, negative symptoms, and the total scores of PANSS. The OCD-schizophrenia patients had higher IQs. No difference was found in MQ. Although the EIQ did not differ between the two groups, the OCD-schizophrenia patients performed better at the Stroop-interference and verbal fluency tests, which was highly dependent on executive function. CONCLUSION: Our findings suggest that OCD may have a protective effect on some cognitive function, at least in relatively early stage of illness. Moreover, based on clinical, neurocognitive features, schizophrenia with OCD could be considered as a distinct subtype of schizophrenia.

Keyword

Schizophrenia; Obsessive compulsive disorder; Cognitive function

MeSH Terms

Adult
Depression
Executive Function
Humans
Intelligence
Intelligence Tests
Memory
Obsessive-Compulsive Disorder
Schizophrenia
Verbal Learning