Can smoking affect cognition in bipolar patients

Abstract

Background Smoking is highly prevalent in bipolar patients. In addition, cognitive dysfunctions are reported in most of the bipolar patients even in remission state. Does this mean that smoking can affect cognition in bipolar patients similar to what is hypothesized in schizophrenic patients? Objective The objective of this research was to study the correlation between smoking and cognitive dysfunction in bipolar patients. Participants and methods A total of 150 bipolar patients (50 manic, 50 depressed, and 50 euthymic) in Maamoura Hospital were compared with 50 controls regarding smoking, Hamilton Depression Rating Scale, Young Mania Rating Scale, and cognitive functions using Wisconsin Card Sorting Test and digit span test and digit symbol test. Results The percentage of smoking was significantly higher in all patients’ groups compared with the control group. No statistically significant relations were found between performance on the Wisconsin Card Sorting Test-128, digit span neither forward nor backward digit span subtest of the Wechsler Adult Intelligence Scale − Revised (WAIS-R), the digit symbol substitution test (the digit symbol subtest of the WAIS-R) and smoking in manic, depressed, and control groups. A statistically significant positive relation was found between performance of the euthymic patients in forward digit span subtest of the WAIS-R and smoking. Conclusion Smoking may have a positive effect on sustained attention of bipolar patients during euthymic state, but not in active illness state. Further research is needed to disclose how we can exploit the beneficial cognitive effect of nicotine by avoiding the deleterious effect of tobacco smoking.