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

Abstract

ObjectiveWe investigated the neurocognitive deficits in schizophrenic patients with and without obsessive-compulsive disorder (OCD).MethodsWe 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).ResultsTen 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.ConclusionOur 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.

Associations of obsessive–compulsive symptoms with clinical and neurocognitive features in schizophrenia according to stage of illness

“…Th ese differen t findin gs m ay be related to th e varying study population and the diverse n ature of obsessivecom pulsive sym ptom s in sch izophren ic illn ess. In addition, type and dosage of an tipsychotics w ere not evenly distributed am on g groups according to th e presence of obsessive-com pulsive sym ptom s in m any previous studies (Rajkum ar et al, 2008;Lee et al, 2009;Tum kaya et al, 20 09;Ow ashi et al, 2010;Sch irm beck et al, 2013a). Particularly, previous findings th at populations w ith obsessive-compulsive symptoms are more likely to have longer duration of illn ess or take clozapin e, w h ich is m ain ly u sed in treatm ent refractory patients, m ay confoun d study results w ith poorer outcom e (Patel et al, 2010;Schirm beck et al, 2013a).…”

“…A recent study w ith a large sam ple including unaffected relatives did n ot fin d a clear association between obsessive-com pulsive sym ptom s and cognitive perform ance, whereas patients with schizophrenia and obsessive-com pulsive sym ptom s displayed a m ore severe clinical profile (Meijer et al, 2013). In contrast, a few studies reported that com orbid obsessivecom pulsive sym ptom s w ere associated w ith better neurocognitive functioning in schizophrenia patien ts w ith less than 10 years m ean illn ess duration an d proposed th at obsessive-com pulsive sym ptom s m ay have a protective effect in the early stages of schizophrenia (Borkowska et al, 2003;Lee et al, 2009). How ever, th ose studies used sm all sam ples w ith few er than 30 patients w ith sch izophren ia.…”

“…Wh ile som e studies reported a negative im pact of com orbid obsessivecom pulsive sym ptom s on clinical outcom es in sch izophrenia (Berm an et al, 1998;Hw ang et al, 20 00;Cunill et al, 2009;Lysaker et al, 2009;Patel et al, 2010;Üçok et al, 2011), others foun d n o association (Wh itn ey et al, 2004;On gur an d Goff, 2005;Tum kaya et al, 20 09;Tiryaki an d Ozkorum ak, 2010). A few stu dies even reported less severe psych otic sym ptom s or cognitive im pairm ent in schizophrenia patients w ith com orbid obsessive-com pu lsive sym ptom s, particularly at the early stage of illness (Poyurovsky et al, 1999;Borkow ska et al, 20 03;Bottas et al, 2005;Lee et al, 2009). Th ese differen t findin gs m ay be related to th e varying study population and the diverse n ature of obsessivecom pulsive sym ptom s in sch izophren ic illn ess.…”

Longitudinal association between cognitive performance and obsessive–compulsive symptoms in patients with psychosis and unaffected siblings

“…While some studies found OCS to be linked to cognitive deficits , others found no evidence for cognitive differences between schizophrenia patients with or without co‐occurring OCS . Some studies even reported better performance of the comorbid group within patients with schizophrenia or in the at risk mental state of psychosis .The inconsistency of results may partly be explained by the cross‐sectional nature of most studies. To the best of our knowledge, only two studies prospectively assessed neurocognitive functioning in comorbid samples over time.…”

Comorbid obsessive-compulsive symptoms in schizophrenia: contributions of pharmacological and genetic factors

“…Findings have been contradicting. Whereas some investigations did not find any significant differences (Hermesh et al, 2003; Whitney et al, 2004; Öngür and Goff, 2005; Tumkaya et al, 2009; Tiryaki and Ozkorumak, 2010; Achim et al, 2011; Meijer et al, 2013), others even suggested that OCS may be associated with better cognitive abilities (Lee et al, 2009; Borkowska et al, 2013), especially in the prodromal states of schizophrenia (Van Dael et al, 2011; Fontenelle et al, 2012; Hur et al, 2012; Zink et al, under review). Most results, however, showed more pronounced deficits in the described domains of executive functioning (Hwang et al, 2000; Lysaker et al, 2002, 2009), cognitive flexibility (Kumbhani et al, 2010; Patel et al, 2010), and also delayed visual memory (Berman et al, 1998; Schirmbeck et al, 2011).…”