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Schizophrenia with comorbid OCD marked by set-shifting deficits
By Andrew Czyzewski, MedWire News
11 May 2010
Psychol Med 2010; 40: 921–933
Patients with comorbid schizophrenia and obsessive compulsive disorder (schizo-OCD) show more severe deficits in attentional set-shifting than patients with schizophrenia only, research shows.
Set-shifting reflects cognitive flexibility, which is thought to recruit the prefrontal cortex, and the researchers speculate that this deficit is a trait marker for schizo-OCD.
There are large variations in the documented prevalence of schizo-OCD, with estimates ranging from 0.5 to 59.2%, both in first episode and in chronic schizophrenia, study co-author Keith Laws (University of Hertfordshire, Hatfield, UK) and colleagues observe.
It remains unclear if this reflects a true comorbidity, more severe illness, or perhaps a unique diagnostic subcategory of schizophrenia.
“Neuropsychological assessment using standardized neuro-cognitive tasks with well understood neural underpinnings may be one way of evaluating the different neural contributions to schizophrenia with OCD,” Laws et al comment in the journal Psychological Medicine.
To do this, the researchers used the Cambridge Automated Neuropsychological Test Battery (CANTAB) – a computer touch-screen test that examines a range of neuro-cognitive functions that tap into the frontal lobes and their subcortical connections.
They recruited 12 patients with schizo-OCD and 16 schizophrenia patients without OCD symptoms. The groups were matched for IQ, gender, age, medication, and duration of illness.
The researchers found that the schizo-OCD patients made significantly more errors on the intra- and extra-dimensional (ID-ED) task of attentional set-shifting than patients with schizophrenia only.
By contrast, there was no significant difference between the groups on the Stockings of Cambridge task, the Cambridge Gamble Task, or the Affective Go/NoGo tasks.
Notably, there was no correlation between ID-ED performance and severity of schizophrenia, OCD, or depressive symptoms, consistent with this neurocognitive impairment being a trait rather than state marker, Laws et al say.
They comment: “Such an overlap has important implications for understanding the neurobiology of this complex, disabling disorder and generating new pharmacological and psychological treatment targets.”
Laws et al add that future research should expand into other key neuropsychological areas implicated in schizophrenia and OCD, such as memory, motor impulsivity and affective processing.
Abstract
By Andrew Czyzewski, MedWire News
11 May 2010
Psychol Med 2010; 40: 921–933
Patients with comorbid schizophrenia and obsessive compulsive disorder (schizo-OCD) show more severe deficits in attentional set-shifting than patients with schizophrenia only, research shows.
Set-shifting reflects cognitive flexibility, which is thought to recruit the prefrontal cortex, and the researchers speculate that this deficit is a trait marker for schizo-OCD.
There are large variations in the documented prevalence of schizo-OCD, with estimates ranging from 0.5 to 59.2%, both in first episode and in chronic schizophrenia, study co-author Keith Laws (University of Hertfordshire, Hatfield, UK) and colleagues observe.
It remains unclear if this reflects a true comorbidity, more severe illness, or perhaps a unique diagnostic subcategory of schizophrenia.
“Neuropsychological assessment using standardized neuro-cognitive tasks with well understood neural underpinnings may be one way of evaluating the different neural contributions to schizophrenia with OCD,” Laws et al comment in the journal Psychological Medicine.
To do this, the researchers used the Cambridge Automated Neuropsychological Test Battery (CANTAB) – a computer touch-screen test that examines a range of neuro-cognitive functions that tap into the frontal lobes and their subcortical connections.
They recruited 12 patients with schizo-OCD and 16 schizophrenia patients without OCD symptoms. The groups were matched for IQ, gender, age, medication, and duration of illness.
The researchers found that the schizo-OCD patients made significantly more errors on the intra- and extra-dimensional (ID-ED) task of attentional set-shifting than patients with schizophrenia only.
By contrast, there was no significant difference between the groups on the Stockings of Cambridge task, the Cambridge Gamble Task, or the Affective Go/NoGo tasks.
Notably, there was no correlation between ID-ED performance and severity of schizophrenia, OCD, or depressive symptoms, consistent with this neurocognitive impairment being a trait rather than state marker, Laws et al say.
They comment: “Such an overlap has important implications for understanding the neurobiology of this complex, disabling disorder and generating new pharmacological and psychological treatment targets.”
Laws et al add that future research should expand into other key neuropsychological areas implicated in schizophrenia and OCD, such as memory, motor impulsivity and affective processing.
Abstract
