A longitudinal study of smoking cessation among primary care patients with depressive symptoms

Conference: 
SAPC ASM 2015 - Oxford - Evidence and innovation in primary care
Talk Code: 
EP3C.8

The problem

Smoking related disease is a leading cause of the 25 year mortality gap between people with a mental illness and those without. One third of people with mental illness smoke and they consume almost half of all cigarettes purchased. In the primary care setting, people with depressive symptoms are more likely to take up smoking and are less likely to quit. One of the barriers to quitting is the fear that nicotine withdrawal will exacerbate psychiatric symptoms. While psychiatric symptoms might increase in the short term, whether or not smoking cessation is associated with changes in depression and anxiety symptoms longer term is not well understood as there are no studies examining the natural history of depression or anxiety symptoms in primary care patients after they quit smoking. The current study addresses this gap by analysing data from a longitudinal naturalistic cohort study of primary care patients with depressive symptoms to explore the rates and predictors of smoking and smoking cessation and to investigate whether smoking cessation was associated with an increase in the severity of depression or anxiety symptoms.

The approach

This study tracks smoking cessation rates among primary care patients with current depressive symptoms over four years and examines whether cessation is associated with changes in depression and anxiety symptoms at 12 month follow-up. This is a prospective cohort study with four annual postal follow-ups. 789 participants with current depression (Center for Epidemiologic Studies Depression scale score of ?16) were recruited from 30 randomly selected urban and rural general practices in Victoria, Australia. The Primary Care Evaluation of Mental Disorders Patient Health Questionnaire (PHQ-9) assessed current depression and anxiety symptoms at baseline and at 12 months.

Findings

At baseline, 248 out of 785 (31.7%) participants smoked. At 12 months, 20 out of 175 (11.4%) participants reported quitting. Quitters had higher levels of social integration and were less likely to have a chronic illness. Paired t-tests showed that quitters reported a significant reduction in depression scores (p =0.05) and a decline in anxiety scores at 12 months. Only 6 (5.7%) participants remained quit over four years.

Consequences

This is the first naturalistic study of smoking cessation in a cohort of primary care attendees with depressive symptoms. It found that rates of smoking are high, and long term cessation is very low, among primary care patients with depressive symptoms. Smoking cessation did not result in a worsening of depressive or anxiety symptoms. These results suggest that motivation to quit could be enhanced if smokers with depression were advised that their depressive symptoms may improve following longer term smoking cessation. GPs should provide additional monitoring and support to assist smokers with depression quit and remain quit.

Credits

  • Sandra Davidson, National Addiction Centre at the Institute of Psychiatry, Kings College, London, UK
  • Gail Gilchrist
  • Aves Middleton, National Addiction Centre at the Institute of Psychiatry, Kings College, London, UK
  • Helen Herrman, National Addiction Centre at the Institute of Psychiatry, Kings College, London, UK
  • Kelsey Hegarty, National Addiction Centre at the Institute of Psychiatry, Kings College, London, UK
  • Jane Gunn, National Addiction Centre at the Institute of Psychiatry, Kings College, London, UK