Smoking and mental health - NCSCT

Epidemiology of the association between smoking and mental disorders 4
with learning difficulties, there was no significant effect on mental disorder
incidence. 4 In the third study, smoking significantly increased the risk of
psychiatric diagnoses in 6442 US Marines deployed to combat zones (hazard rate
[HR] = 1.75, 95% CI 1.44–2.12). 5
4.4 Smoking and developmental and emotional disorders
Twenty-one papers assessed the association between smoking and developmental
and emotional disorders, 6–26 of which two used the same cohort of
participants 14,15 (see Table A1). All of these studies assessed the effect of
developmental and/or emotional disorders on the risk of becoming a smoker;
only one study 16 also investigated the effect of smoking on the risk of
developmental disorders. Twenty of the included studies examined the
associations prospectively, and one 6 used retrospective methods. Thirteen studies
were carried out in North America, five in Europe and three in Australasia. Most
included data from males and females, generally in equal proportions, one study
included females only 23 and three studies males only. 10,11,19
Although all studies looked at the longitudinal relationship between
developmental disorders and smoking initiation, only seven of the studies
restricted their analyses to non-smokers at baseline, 7,13,15,21–24,26 but one study
reported having repeated analyses excluding smokers at baseline and obtaining
similar results; data were not reported, however. 12
The range of developmental disorders assessed included attention deficit
hyperactivity disorder (ADHD; seven studies 7–10,12,21,26 ), conduct disorder (CD;
thirteen studies 6,8–12,14,15,17,19,20,23,26 ), inattention (three studies 11–13 ),
hyperactivity–impulsivity (three studies 11,12,15 ), hyperactivity (five
studies 13,14,16,19,25 ), oppositional defiant disorder (three studies 11,14,26 ),
internalising disorder (two studies 16,22 ), externalising disorder (one study 22 ), and
composite measures of behavioural disorders (four studies 16,18,19,24 ) and
emotional disorders (one study 8 ).
4.4.1 Composite measures of behavioural and emotional disorders
A meta-analysis of three studies 18,19,24 demonstrated that children with
behavioural disorders were at significantly increased risk of initiating smoking
compared with children without behavioural disorders (RR = 1.23, 95% CI
1.07–1.42, I 2 = 0% – Fig 4.1). In addition, a meta-analysis of two studies 16,18
found that people with behavioural disorders were almost more than twice as
likely to become daily/regular smokers compared with those without behavioural
disorders (RR = 2.11, 95% CI 1.16–3.85, I 2 = 62% – Fig 4.1). Data from one
further study found that emotional disorders were not significantly associated
with smoking onset (prevalence ratio 1.13 8 ).
© Royal College of Physicians 2013 65