Aims The effect of successful and unsuccessful smoking cessation on depressive mood, anxiety- and suicide-related outcomes is unclear. The aim of this secondary analysis was to explore the relationship between abstinence status and these outcomes.
Design Cohort of adult smokers attempting to stop smoking. Smoking status was assessed by a daily diary; depressed mood, anxiety and suicidal tendencies by the Hamilton Depression Rating Scale (HDRS). The association of complete and point-prevalence abstinence with the HDRS variables was assessed using multi-level linear regression models.
Setting Randomized trial of sertraline versus placebo for smoking cessation with weekly behavioural support provided in a clinic.
Participants A total of 133 adult smokers with past major depression.
Findings Pre-quit mood scores did not predict smoking status post-quit day. Both continuous and point-prevalence abstainers had significantly lower total HDRS, suicide and anxiety scores, adjusted for all potential confounders, during the period following quit day than did non-abstainers who experienced a significant mood deterioration. There was a significant effect of sertraline on post-quit HDRS scores but not on abstinence.
Conclusions Contrary to expectation, smoking abstinence among smokers with a history of major depression did not lead to increase in depression, anxiety or suicide ideation; however, failed quit attempts did. Persisting with a quit attempt while unable to achieve abstinence may be associated with mood deterioration.