Tobacco exacerbates cognitive dysfunction in mentally-ill women, reports study from RML

Recent data suggest that women availing psychiatric services with major mental illnesses (MMI) are three times as likely to use tobacco, as women from the general population in Delhi. Now, Khobragade et al have reported in Psychiatry Research journal that tobacco use may exacerbate the cognitive dysfunction associated with MMI among women. 

Cognitive effects of tobacco use among women with schizophrenia, bipolar disorder, or depression have not been studied extensively as most studies focussed on men smokers.

Tobacco use whether smoked or smokeless- adversely affects cognitive functioning but because of its short-term effects on the brain cholinergic system, nicotine improves attention, working memory, and executive functions through arousal. But recent research has suggested that smoking is associated with a decline in verbal memory, MMSE scores, and executive function.

To find out the prevalence of tobacco use, and additively to assess cognitive effects of tobacco use among using and non-using women with these mental illnesses, a cross-sectional study was carried out in New Delhi's community-dwelling women with either schizophrenia (SZ), bipolar disorder (BD) or recurrent depressive disorder (RDD), diagnosed clinically. A total of 321 patients were recruited.

To provide cognitive functioning estimates based on general intelligence, memory, and perceptual acuity, the questionnaires used were: The Global Adult Tobacco Survey (GATS), Fagerstrom Test for Nicotine Dependence (FTND) (Smoke and Smokeless), Post Graduate Institute (PGI) Battery of Brain Dysfunction (PGI BBD) Information Questionnaire (Info Q). Trail Making Test A and B (TMT A and B) questionnaire was used to assess the aspects of cognition such as visual scanning, psychomotor speed, complex attention, and mental flexibility.

It was found that

1. Among women who were clinically diagnosed as SZ, BD, or RDD, 14.64% had 'ever' used tobacco and 12.41% were using tobacco currently.

2. A large number of current smokers were dependent nicotine users, with FTND scores highest for SZ followed by BD and RDD.

3. Users (both smoke and smokeless forms) were older and less educated.

4. Tobacco users answered statistically significantly fewer questions on the PGIBBD Information Questionnaire.

5. Users also took significantly more time to complete both TMT-A and TMT-B.

6. Age, years of schooling, and tobacco use were all significant co-variates for performance on cognitive tests.

It was inferred that tobacco users had lower motor speed and lesser visual scanning, poorer flexibility of thinking and working memory. Women with schizophrenia performed the worst. Older age is a significant factor for poor cognitive functioning but smoking can accelerate cognitive decline in non-demented elderly.

Smoking is the major cause of preventable deaths worldwide, and although there is a decline in overall smoking prevalence in developed countries, the decline in women is less pronounced than in men. Women become dependent faster and experience greater difficulties in quitting.

Source: Khobragade B, Sharma V, Deshpande SN. Cognitive function in women with major mental illnesses who use tobacco. Psychiatry Res. 2020 Nov 27;295: 113603. doi: 10.1016/j.psychres.2020.113603