Smoking and mental health - NCSCT

Smoking and mental health
colleagues 96 found that higher depression and anxiety scores increased risk of
smoking initiation, and that higher depression symptom levels were associated
with earlier smoking initiation, whereas no relationship was reported by Wang
and colleagues. 102 In a study using real-time data collection, Whalen and
colleagues found that negative affect preceded daily occurrences of smoking. 103
Among young adult smokers, Breslau and colleagues 104 found that a history of
major depression predicted progression to dependence and more severe levels of
dependence; however, a history of anxiety disorder did not predict progression.
These investigators also found that a history of tobacco dependence predicted
onset of major depression. McKenzie and colleagues 105 found that higher
depression and anxiety symptoms predicted progression to tobacco dependence
in young adulthood, 102,106 whereas Audrain-McGovern et al 96 found that regular
smoking was associated with a decrease in depression symptoms, consistent with
a self-medication model. Further evidence on these associations is provided in
Chapter 4. Individuals with major depression have been found to have increased
vulnerability to a mood disorder relapse during abstinence from smoking,
particularly those with histories of recurrent depression. 107 However, history of
depression does not appear to influence the likelihood of successful smoking
cessation. 108
3.4 Schizophrenia
The prevalence of tobacco smoking among patients with schizophrenia is
extremely high (see Chapter 2), as are levels of dependence on tobacco in this
patient group. 46
3.4.1 Evidence from genetic studies
The relationship between smoking and schizophrenia has rarely been explored in
a genetic epidemiological framework. Thus, it remains unclear whether a
common genetic and/or environmental liability contributes to the association.
One study of twins discordant for schizophrenia found that unaffected co-twins
were more likely to smoke, more likely to experience some withdrawal symptoms
and less successful at quitting compared with control individuals. 109 The authors
concluded that familial factors – encompassing both genetic and environmental
factors – contributed to the phenotypic association between smoking and
schizophrenia. Molecular genetic studies suggest that variation within the 15q13-
q14 chromosomal region, which encompasses an nAChR subunit, is associated
with both schizophrenia and tobacco dependence. 110–114 These associations are
potentially mediated by sensory gating deficits observed in individuals with
schizophrenia; 115 nicotine normalises this deficit. 116 Given the strong association
between schizophrenia and smoking, this is a promising area for future research.
46 © Royal College of Physicians 2013