Broad spectrum psychiatric comorbidity is associated with better executive functioning in an inpatient sample of individuals with schizophrenia.

BACKGROUND Individuals with schizophrenia exhibit cognitive deficits but whether these deficits are exacerbated by broad spectrum psychiatric comorbidity (i.e., comorbidity that is inclusive of disorders from different diagnostic categories) is unclear. A broad spectrum approach to psychiatric comorbidity is an ecologically valid way to capture the diagnostic heterogeneity inherent in psychiatric presentations. OBJECTIVE This study compared the attention, working memory, processing speed, and executive functioning of individuals with schizophrenia only relative to individuals with schizophrenia and broad spectrum psychiatric comorbidity. METHOD Archival patient neuropsychological test data were obtained for a sample of patients with schizophrenia only (n=30) and a sample of patients with schizophrenia and psychiatric comorbidity (n=33). Relevant tests were used to form composite indices for the cognitive domains of attention, working memory, speed of processing, and executive functioning. RESULTS Unexpectedly, individuals with schizophrenia and psychiatric comorbidity had significantly better executive functioning than individuals with schizophrenia only. There were no other significant differences. CONCLUSIONS A broad spectrum approach to psychiatric comorbidity can help to account for differences in the executive functioning of individuals with schizophrenia. In clinical settings, individuals with schizophrenia and psychiatric comorbidity may benefit from intervention strategies that capitalize on their relatively higher executive functioning.