An application of the stress-diathesis model: A review about the association between smoking tobacco, smoking cessation, and mental health

Background: Worldwide, approximately 24% of all adults smoke, but smoking is up to twice as prevalent in people with mental ill-health. There is growing evidence that smoking may in fact be a causal risk factor in the development of mental health disorders, and that smoking cessation leads to improved mental health. Methods: In this scholarly review we have: (1) used a modern adaptation of the Bradford-Hill criteria to bolster the argument that smoking could cause mental ill-health and that smoking cessation could reverse these effects, and (2) by considering psychological, biological, and environmental factors, structured the evidence to-date into a classic stress-diathesis model. Results: Our model suggests that smoking is a psychobiological stressor, but that the magnitude of this effect is mediated by the individuals’ diathesis to develop mental ill-health and other vulnerability and protective factors. We explore biological mechanisms that underpin the model, such as tobacco induced damage to neurological systems and oxidative stress pathways. Furthermore, we discuss evidence indicating that it is likely that these systems repair after smoking cessation, leading to better mental health. Conclusion: Based on a large body of literature including experimental, observational, and novel causal inference studies, there is consistent evidence showing that smoking can negatively affect the brain and mental health, and that smoking cessation could reverse the mental ill-health caused by smoking. Our model suggests that smoking prevention strategies have a role in preventing mental illness as well as physical illness.