Tobacco smoking is associated with better cognitive performance in smokers with schizophrenia : a thesis presented in partial fulfilment of the requirements for the degree of Masters in Science in Psychology at Massey University

Abstract

Past research argues people with schizophrenia (P/S) exhibit a specific cognitive deficit. This study argues dopamine deficiency and debilitating anxiety reduce cognitive functioning in P/S and over 80 per cent of P/S actively smoke to replenish dopamine and reduce debilitating anxiety, which relates to improved cognition. Comparing 18 smokers and 8 non-smokers with schizophrenia, with each other, and with 20 smoking and 20 non-smoking non-psychiatric people we used an independent samples between groups 2 by 2 correlational design to determine two main hypotheses: smokers with schizophrenia, after smoking one cigarette, in comparison to non-smokers with schizophrenia, will score fewer Wisconsin Card Sorting Test (WCST) errors: non-psychiatric people will perform better than P/S on the WCST. Results showed smokers with schizophrenia performed better on the WCST than non-smokers with schizophrenia. Smoking accounted for 11.2 % and facilitating-anxiety 41.3 % of the variance between schizophrenia groups. When controlling for facilitating-anxiety the significant difference dissolved. Smoking did not influence subjective affect or physiological arousal. Diagnosis did not influence cognitive functioning and the influence of smoking on cognitive performance did not depend on diagnosis. The discussion made four main conclusions: tobacco smoking and facilitating-anxiety directly related to cognitive performance in smokers with schizophrenia when completing the WCST, smoking does not influence subjective affect in smokers with schizophrenia when subjectively relaxed, schizophrenia does not exhibit a specific cognitive deficit, although smokers with schizophrenia did not gain the most from smoking clinical observation and literature review implies they actively smoke to obtain medicinal and psychological benefits.