Smoking and mental health - NCSCT

More documents

Recommendations

Info

Smoking and mental health withdrawal could not be ruled out, however. Levin et al 117 were unable to demonstrate an effect of nicotine on selective attention in smokers with schizophrenia. Depatie and colleagues 126 suggest that differences in findings between these two studies may indicate that nicotine has differential effects on two different aspects of attention. The great majority of people with schizophrenia begin smoking before the onset of psychosis. 128 Weiser and colleagues 129 investigated the hypothesis that future schizophrenia patients had higher rates of smoking before the manifestation of psychosis and the diagnosis and treatment of schizophrenia than non-psychiatric controls. Over 14,000 Israeli participants were recruited in late adolescence and followed an average of 10 years. These investigators found that the risk of developing schizophrenia during follow-up was twofold greater among smokers than non-smokers, and that among smokers this effect was exposure related. In a Swedish study of over 50,000 young adults, however, Zammit and colleagues 130 found that cigarette smoking was prospectively associated with a lower risk of developing schizophrenia. These investigators speculated that nicotine may have a modest neuroprotective effect for the development of schizophrenia, through nicotine effects on nAChRs and DA systems in the brain. A recent study, in which pre-morbid smoking was associated with later onset of schizophrenia, adds support to this interesting possibility; 131 relevant data are reviewed in more detail in Chapter 4. Individuals with schizophrenia appear to have an increased intensity of withdrawal symptoms during the first 2 weeks after a cessation attempt; 132 however, many outcome studies in which individuals with schizophrenia stop smoking do not find a long-term deterioration in schizophrenia symptoms or increased psychotic relapses. 107 3.5 Attention deficit hyperactivity disorder A link between ADHD and smoking has been documented repeatedly, even among adolescents with subclinical levels of ADHD characteristics. 133 3.5.1 Evidence from genetic studies The relationship between smoking and ADHD is complex, with maternal smoking during pregnancy long held to be a risk factor for offspring with ADHD. 134,135 It is possible that the relationship is confounded by a genetic correlation between maternal smoking and attentional/behavioural problems in the offspring. Furthermore, some twin studies have suggested that the association is less robust than previously thought; 136,137 however, such studies have not directly addressed whether the phenotypes are genetically or environmentally correlated in the offspring. Nevertheless, there are suggestions of a genetic 48 © Royal College of Physicians 2013
Neurobiological and behavioural mechanisms linking smoking and mental disorders 3 correlation in the literature: one adolescent twin study reported high genetic, and moderate-to-high environmental, correlations between a general externalising liability factor and nicotine use, 138 although ADHD was not directly measured. Few molecular genetic studies have explored the effects of specific genetic variants on both smoking/tobacco dependence and ADHD. However, evidence from a rat model of ADHD, which exhibits nicotinic receptor deficits relative to wild-type animals, 139 suggests that some such variants exist. Genome-wide association studies (GWAS) of ADHD have reported a modest association with variation (including duplications) in the human homologue of the same receptor subunit. 140,141 These findings are promising, and future work should utilise more global approaches (eg GWAS, twin studies) to explore additional shared genetic and environmental risk factors contributing to the phenotypic association. Although the precise nature of the relationship has yet to be untangled, clinicians should note that maternal smoking – particularly during pregnancy – and adolescent smoking are reasonably robust indicators of a liability to ADHD. 3.5.2 Evidence from animal studies ADHD is routinely treated using drugs (eg methylphenidate and dexamphetamine) with stimulant properties, which resemble to some extent the psychopharmacological properties of nicotine. Smoking is more prevalent in patients with ADHD and it seems reasonable to suggest that patients with this condition may use tobacco as a form of self-medication. Although a number of authors have discussed their findings in the context of rationalising the putative role of ADHD in tobacco dependence, few studies have sought to explore the effects of nicotine in animal models of ADHD specifically. Studies with experimental rats and mice suggest that nicotine can improve sustained attention in some tasks such as the five-choice serial reaction time task (5CSRTT) 142–145 or a signal detection task. 146,147 In the latter task, nicotine also attenuates the deficit in attention evoked by the N-methyl-D-aspartate (NMDA) receptor antagonist dizolcipine. 148,149 It has been suggested that the neurobiological mechanisms that underpin the ability of nicotine to improve attention and, especially, attenuate the impairment of attention may explain the vulnerability of patients with ADHD to nicotine/tobacco dependence. 118 Other studies have shown that nicotine improves attention and vigilance in performing the 5CSRTT in animals that exhibit less than optimal (90% correct). 150 This group also noted, however, that, in rats pre-treated with nicotine using a regimen designed to elicit sensitisation to the drug, nicotine evoked a significant increase in anticipatory responding which may be characteristic of disinhibition or impulsivity. Previous studies, using a different experimental paradigm, also suggest that repeated or chronic nicotine elicits disinhibition in experimental © Royal College of Physicians 2013 49
Page 1 and 2:
PDF not for circulation Smoking and
Page 3 and 4:
Contents Members of the Tobacco Adv
Page 5 and 6:
Contents 4.4.3 Attention deficit hy
Page 7 and 8:
Contents 6.4.3 Staff knowledge 122
Page 9 and 10:
Contents 10.5 Tobacco policy and me
Page 11 and 12: Contributors Anthony Aclet - Specia
Page 13 and 14: Contributors Jill Williams - Associ
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
Page 61: Neurobiological and behavioural mec
Page 77 and 78: Epidemiology of the association bet
Page 99 and 100: Smoking cessation interventions for
Page 113 and 114:
Smoking cessation interventions for
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
6 Population strategies to prevent
Page 127 and 128:
Population strategies to prevent sm
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Smoking and mental disorders: speci
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
The economic cost of smoking in peo
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Ethical and legal aspects 9 pose co
Page 199 and 200:
Ethical and legal aspects 9 less an
Page 201 and 202:
Ethical and legal aspects 9 patient
Page 203 and 204:
10 Summary and conclusions 10.1 Smo
Page 205 and 206:
Summary and conclusions 10 10.4 Smo
Page 207 and 208:
Summary and conclusions 10 although
Page 209 and 210:
11 Key conclusions and recommendati
Page 211 and 212:
Key conclusions and recommendations
Page 213 and 214:
Page 215:
show all

Smoking and mental health - NCSCT

Create successful ePaper yourself

Delete template?

Save as template?