The Link Between Smoking and Cognitive Functioning in People with Psychosis

The tobacco epidemic is one of the biggest public health threats the world has ever faced, killing more than 7 million people a year (WHO).

People with psychosis are more likely to smoke compared to the general population and it is believed that this could have a negative impact on cognitive functioning.

A recent study, published in the American Journal of Psychiatry, has analysed the association between peoples’ current smoking behaviour and performance on cognitive tasks, whether a longitudinal link between smoking behaviour and cognitive functioning exists, and if smoking cessation can improve peoples’ cognitive functioning.

The researchers compared people with non-affective psychosis, their unaffected siblings and healthy individuals.

Results found that:

• At baseline, 66.6% of the patients smoked, compared with 38.3% of the siblings and 25.2% of the control subjects.
• Among the patients, there was a link between smoking and lower performance on cognitive processing speed
• Within the unaffected sibling group, there exists a negative link between smoking status and working memory, reasoning and problem-solving.
• Within the health control group, there was a significant association between smoking behaviour and lower cognitive processing speed.
• There is an association between smoking cessation and better performance on processing speed among the patients who quit smoking. The results show that even changes in the number of cigarettes smoked per day were linked with cognitive functioning improvement.

Overall the results show that smoking is positively linked with lower performance in many cognitive functions for all of the groups tested. The evidence for the link between smoking cessation/ reduction and cognitive functioning improvement highlights the benefits of incorporating smoking cessation support into evidence-based interventions for people with psychosis.