Smoking and mental health - NCSCT

Smoking and mental health
Relative risk (RR)
Relative risk (RR)
Study or subgroup IV, random, 95% Cl IV, random, 95% Cl
Initiation or use
Brown 1996a 2.00 [0.87, 4.62]
McGee 1998 1.32 [0.87, 2.00]
Niemelä 2009 (heavy) 1.20 [1.03, 1.40]
Subtotal (95% CI) 1.23 [1.07, 1.42]
Heterogeneity, tau 2 = 0.00; chi 2 = 1.51, df = 2 (p = 0.47); I 2 = 0%
Test for overall effect: Z = 2.86 (p = 0.004)
Daily or regular smoking
Goodman 2010 2.83 [1.73, 4.64]
McGee 1998 1.53 [0.87, 2.68]
Subtotal (95% CI) 2.11 [1.16, 3.85]
Heterogeneity, tau 2 = 0.12; chi 2 = 2.60, df = 1 (p = 0.11); I 2 = 62%
Test for overall effect: Z = 2.43 (p = 0.01)
Test for subgroup differences: Chi 2 = 2.92, df = 1 (p = 0.09); I 2 = 65.7%
0.2
0.5
MH disorder reduces risk
1
2 5
MH disorder increases risk
Fig 4.1 Behavioural disorders in children and adolescents and the onset of
smoking. MH, mental health.
4.4.2 Internalising and externalising problems
Two studies reported the association between smoking and internalising or
externalising problems. 16,22 Internalising problems were not significantly
associated with smoking initiation or use (RR = 1.24, 95% CI 0.78–1.96, I 2 =
80%, two studies 16,22 ), or with daily or regular smoking (RR =1.02, 95% CI
0.99–1.05, one study 22 ). People with externalising problems were no more likely
to initiate smoking (RR = 1.02, 95% CI 0.98–1.06), but were slightly more likely
to progress to regular smoking (RR = 1.07, 95% CI 1.03–1.11), although this
association is based on the findings from only one study. 22 Data from one study
found that smoking was not a determinant of an increased risk of onset of
internalising disorders (RR = 0.77, 95% CI 0.36–1.64). 16
4.4.3 Attention deficit hyperactivity disorder
A meta-analysis of five studies 7,9,10,12,21 demonstrated that people with ADHD
were more likely to start smoking than those without the disorder (RR = 1.75,
95% CI 1.31–2.34, I 2 = 56% – Fig 4.2). Two further studies could not be included
in the meta-analysis because no suitable data were reported; 8,26 one of these
reported a significant threefold increase in the risk of onset of daily smoking (RR
= 3.1, p 0.05). 8
When looking at the subtypes of ADHD, pooled analyses found that
hyperactivity–impulsivity was not significantly associated with smoking
66 © Royal College of Physicians 2013