Smoking and mental health - NCSCT

Neurobiological and behavioural mechanisms linking smoking and mental disorders 3
Finally, studies have demonstrated that attentional processes and other
cognitive functions (eg concentration) are mediated by cholinergic systems in
the prefrontal, occipital and parietal cortices of the brain, as well as the
amygdala, hippocampus and anterior cingulate cortex. 42 The nAChRs are
widely expressed in these areas of the brain 43 and experimental manipulation
of these receptors affects attention-related task performance in animal
studies. 44 Several studies have indicated that nAChRs, and specifically the α 7
subtype in the hippocampus, may be crucial in sensory gating. 45 Deficits in
sensory gating are characteristic in people with schizophrenia and studies have
shown that nicotine enhances sensory gating processes in people with this
disorder. 46
3.2.3 Social and psychosocial mechanisms
Psychosocial risk factors for tobacco use among smokers with a mental disorder
are important and often neglected relative to biological factors. Theories of
psychosocial risk for tobacco use typically group variables into four conceptual
domains according to whether they are intrapersonal (eg mood related),
interpersonal (both family and peer related), behavioural (eg rebelliousness,
impulsiveness) or organisational (eg cultural factors, organisational norms and
practices). Of note, there are many known psychosocial risk factors for tobacco
addiction in the general population that are also associated with mental illness,
such as low income, limited education, unemployment, manual and unskilled
occupations, and being single or divorced. These general psychosocial risk factors
complicate the isolation of those who might be susceptible to mental disorders.
In addition, there is a wide range of mental disorders of varying severity,
medication and co-morbidity, and therefore there are many subtypes within the
broad category of mental disorders.
Prospective studies of adolescents and young adults in the general population
have identified several psychosocial risk factors associated with initiation of
tobacco use and escalation to regular smoking, including higher perceived
benefits of tobacco use relative to risks, low levels of parental support and
monitoring, parental use of tobacco, social networks of tobacco-using peers,
and poor school performance. 47,48 However, very few of these risk factors have
been examined in studies of the association between tobacco use and mental
illness.
3.3 Depression and anxiety
The association between tobacco use and depression, and to a lesser extent the
association with anxiety, is widely recognised. Evidence is available on these
associations from a range of sources.
© Royal College of Physicians 2013 41