Thought disorder and executive ability

A neurocognitive model of thought disorder is proposed that links: (1) impaired ability to establish set with poverty of speech; (2) impaired ability to maintain set with positive thought disorder; and (3) impaired ability to shift sets with perseveration in speech. The aim of this study is to examine performance on tests sensitive to set ability in patients prone to thought disorder. Patients with schizophrenia (n = 36), mania (n = 18) and a well control group (n = 20) were assessed on two occasions separated by 4 weeks. Testing included: a free speech sample, Controlled Oral Word Association test, Stroop test, Wisconsin Card Sort test, and the Trail Making test. Impaired ability to maintain set in the face of interference was correlated with positive thought disorder, impaired ability to establish set was correlated with poverty of speech, and impaired ability to shift set was associated with perseveration in speech. The associations between impaired set ability and types of thought disorder support a neurocognitive model implicating impaired executive ability in the pathogenesis of thought disorder.