Smoking and mental health - NCSCT

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Smoking and mental health rats. 151,152 Thus, in studies with experimental animals, nicotine, although having some psychopharmacological characteristics of an anti-ADHD agent, does not seem to have all the properties necessary to alleviate all the symptoms of the condition. 3.5.3 Evidence from human studies Studies have supported the hypothesis that nicotine improves cognitive functions in people with ADHD, 153–157 eg Gehricke and colleagues 156 found an effect of nicotine relative to placebo patch on attention and concentration in young adults with ADHD who smoked. Smokers wore a nicotine patch for 2 days and a placebo patch for 2 days, and used electronic diaries to record ADHD symptoms during their normal daily routines. However, it is difficult to distinguish direct effects of nicotine versus withdrawal relief due to nicotine administration in studies such as this where people who smoke regularly are asked to abstain from smoking. Therefore, using a similar design, Gehricke and colleagues 155 investigated the effects of nicotine in young adults with ADHD who both did and did not smoke. They found that nicotine patches improved attention and reduced difficulty concentrating compared with placebo patch in smokers with ADHD. Critically, they found almost identical results for non-smokers. As noted above, studies of the effect of nicotine in non-smokers are important to distinguish between attentional effects resulting from reversal of cognitively based nicotine withdrawal effects (eg impaired concentration) and any beneficial effects that are independent of the reversal of withdrawal symptoms. In their laboratory study investigating the effects of nicotine on ADHD symptoms, Levin and colleagues 157 found that nicotine versus placebo patch enhanced attention in both smokers and non-smokers (the effect was greater in non-smokers); concentration was enhanced only in smokers. Similar effects for nicotine versus placebo on cognitive functioning were found in a study of non-smokers with ADHD. 93 By contrast, Conners and colleagues 154 found an effect for smokers but not non-smokers. Nicotine has also been found to beneficially affect behavioural disinhibition and other symptoms of ADHD, 158 although the results have been inconsistent. 153 In a 4-year prospective study of adolescents, Milberger and colleagues 159 found that ADHD symptoms were significantly related to smoking initiation; at followup, 19% of participants with ADHD had initiated smoking versus 11% without ADHD. In addition, participants with ADHD had an earlier age of onset: 71% of smokers with ADHD began smoking before age 17 compared with 27% of smokers without ADHD. Smoking initiation was also significantly related to psychiatric co-morbidity. The prevalence of cigarette smoking was 10% among participants with ADHD only and 27% in participants with one or more additional psychiatric disorder (eg conduct disorder, anxiety disorder). However, the association between ADHD and smoking initiation remained significant after 50 © Royal College of Physicians 2013
Neurobiological and behavioural mechanisms linking smoking and mental disorders 3 the influence of co-morbidities was statistically controlled. Fuemmeler and colleagues 133 also found that ADHD symptoms were associated with smoking initiation and progression to regular use. Interestingly, however, when these investigators assessed the separate effects of inattentive and impulsive–hyperactive symptoms, only the latter were significantly associated with initiation and progression. Whalen and colleagues 160 found that adolescents with untreated ADHD were more likely to initiate smoking than their counterparts who were receiving medication. In addition, they smoked more regularly. 161 Finally, smokers with ADHD appear to be at risk for severe tobacco dependence. 162 The impairments in attention and concentration characteristic of ADHD are frequently associated with problems in affect regulation and arousal, including depression-impaired anger management. 163,164 In a study described above, Gehricke and colleagues 155 investigated the mood effects of nicotine in adults with ADHD. Although differences were modest, participants reported lower levels of negative affect (nervousness, stress, anger) in the nicotine versus placebo patch condition. Similar between-patch differences were found in both smokers and non-smokers. Bekker and colleagues 153 reported similar results in smokers with ADHD. Small improvements in the mood of non-smokers with ADHD after nicotine versus placebo administration have been observed in other studies. 154,157 3.6 Smoking and dementia Apolipoprotein E genotype has been reported to modify the effect of some exposures for dementia; however, its role as a risk factor for smoking remains controversial, with one large study suggesting stronger associations between smoking and incident dementia in the absence of the ε4 allele, 165 another finding stronger associations in the presence of this allele 166 and a third finding no difference between these strata. 167 Finally, the impact of improving a variety of lifestyles on risk of dementia was recently modelled and it was estimated that each 5% reduction in smoking prevalence would result in a 2% reduction in dementia risk. 168 In terms of potential underlying mechanisms, associations have been reported between smoking and neuritic plaques in a neuropathological follow-up study nested within a large cohort, 167 suggesting direct influences on Alzheimer’s disease progression. However, the effect of smoking on cerebral perfusion 169 and cerebrovascular disease in general is also likely to be important. Understanding of the relationship between smoking and dementia risk has changed dramatically over recent decades, from early suggestions of a protective effect to later confirmation as a risk factor. Meta-analyses have found an association between dementia risk and current smoking, 170,171 but no association with former smoking. 170,171 One recent study has also reported an association between passive smoking and increased dementia risk, 172 with supporting © Royal College of Physicians 2013 51
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PDF not for circulation Smoking and
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Contents Members of the Tobacco Adv
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Contents 4.4.3 Attention deficit hy
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Contents 6.4.3 Staff knowledge 122
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Contents 10.5 Tobacco policy and me
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Contributors Anthony Aclet - Specia
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Page 15 and 16: 1 Mental disorders 1.1 What is a me
Page 17 and 18: Mental disorders 1 1.3 Common menta
Page 19 and 20: Mental disorders 1 1.4.4 Somatisati
Page 21 and 22: Mental disorders 1 In addition to s
Page 23 and 24: Mental disorders 1 not diagnosed un
Page 25 and 26: Mental disorders 1 Similar to many
Page 27 and 28: Mental disorders 1 12 Chang CK, Hay
Page 29 and 30: Mental disorders 1 52 Young S, Toon
Page 31 and 32: Smoking among people with mental di
Page 53 and 54: Neurobiological and behavioural mec
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Smoking cessation interventions for
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6 Population strategies to prevent
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Population strategies to prevent sm
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The economic cost of smoking in peo
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Ethical and legal aspects 9 pose co
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Ethical and legal aspects 9 less an
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Ethical and legal aspects 9 patient
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10 Summary and conclusions 10.1 Smo
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Summary and conclusions 10 10.4 Smo
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Summary and conclusions 10 although
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11 Key conclusions and recommendati
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Key conclusions and recommendations
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