Cognitive functions in smoking and non-smoking patients with schizophrenia: A systematic review and meta-analysis of comparative studies

firemonkey · December 26, 2018, 1:45pm

ncbi.nlm.nih.gov

Cognitive functions in smoking and non-smoking patients with schizophrenia: A systematic review and meta-analysis of comparative studies.

YY Wang, S Wang, W Zheng, BL Zhong, CH Ng, GS Ungvari, CX Wang, YT Xiang and XH Li, Psychiatry research, Dec 2018 10

The "Self-medication hypothesis" that has been developed to explain the effect of nicotine in improving aspects of cognitive impairment in schizophrenia remains controversial. This systematic review and meta-analysis compared cognitive functions between smoking and non-smoking schizophrenia patients. The PubMed, PsycINFO, EMBASE, Web of Science, and Cochrane Library databases were systematically and independently searched. Basic demographic and clinical characteristics, smoking history and cognitive performance were recorded. Seven of the 11 studies included in the study, had meta-analyzable data. Compared to non-smoking schizophrenia patients, their smoking counterparts showed significant deficits on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)-immediate memory (n = 739), the RBANS-total score (n = 739) and the Continuous Performance Test-Identical Pairs (n = 157). Two of the 4 studies without meta-analysable data did not report significant group difference in performance on the Wechsler Digit Span Task and the Beck Cognitive Insight Scale, while the other 2 studies found that non-smokers outperformed than smokers in problem solving and visual learning. In conclusion, this systematic review and meta-analysis found that smoking schizophrenia patients had worse performance in certain cognitive tasks than non-smoking patients, casting doubts on the validity of the "self-medication hypothesis" that needs to be further examined.

Joker · December 26, 2018, 1:49pm

I did not realise there was controversy. I thought the smoking thing was accepted.

i know what I have accepted - smoking is probably going to kill me sooner than sz.

insidemind · December 26, 2018, 4:15pm

I think it helps with working memory in the beginning but fades away.

everhopeful · December 26, 2018, 4:17pm

I think it causes schizophrenia. That’s why so many schizophrenics smoke !

I was doung “ok”-ish until about 26 when I started smoking.

anon94176359 · December 26, 2018, 4:23pm

Interesting. I started smoking a year before sz onset.

firemonkey · December 26, 2018, 4:27pm

In hospital I knew someone who smoked like a chimney all the while muttering to the voices. It’s something I’ve never done. I think I was put off by someone putting tobacco in my tea on one of my last days at prep school. I was violently sick.