Conditional reasoning difficulties in polysubstance-dependent patients.

Abstract

Polysubstance dependence has been associated with many neurocognitive impairments. The present study explored one of these deficits, namely conditional reasoning, using the Wason selection task. In healthy individuals, social contract and precautionary content improve conditional reasoning performance compared with descriptive or abstract content. Twenty-two recently detoxified polysubstance-dependent patients were compared with 22 controls matched for sex, age, and education level on their performance on the Wason selection task across problems involving social contract, precautionary, and descriptive conditional rules, controlling for depression, anxiety levels, and verbal intelligence. Conditional reasoning on descriptive and social contract rules was severely impaired in polysubstance-dependent patients. Precautionary reasoning was also impaired, but to a lesser degree than the other modalities of conditional reasoning. These results may reflect a toxic effect of chronic multiple-drug consumption on the prefrontal areas of the brain. Alternatively, conditional reasoning difficulties could be present, at least partially, before polysubstance dependence onset. This population may have difficulties properly understanding social contracts in real-life settings, suggesting a potential target for clinical intervention.