Depression comparable to smoking

The association between depression and mortality is at a level comparable with smoking, a study in the British Journal of Psychiatry finds. Examining links between depression, anxiety and mortality, the Norwegian population-based study of more than 61,000 participants found the odds ratios for mortality associated with smoking and depression were comparable (HR 1.59, HR 1.52) when adjusted for age and gender. However, depression exceeded that of smoking in fully adjusted models, the study’s authors said. Paradoxically, the study also found that patients who had both anxiety and depression had lower mortality rates compared with depression alone. The authors said this finding was counter-intuitive since comorbid anxiety and depression were associated with poorer physical health and more disability than depression alone. The researchers suggest that people who experience anxiety may be more likely to seek help, adhere to treatment and be less likely to indulge in risky behaviour. “In other words, there may be an evolutionary advantage of moderate levels of anxiety, a hypothesis that requires further evaluation,” they said. Because screening for psychiatric morbidity was limited to symptoms for anxiety and depression, the report’s authors noted that the study did not take into account influences of other mental disorders. “As a result, we cannot rule out possible confounding by comorbidity…or determine the temporal relationship between somatic health states and anxiety/depression,” they said. They said more research is needed in order to go beyond CVD mortality alone and investigate mechanisms underlying the effects of depression. “[Further research] is required to investigate whether modest levels of anxiety promote earlier identification and treatment of potentially life-threatening disease and/or decrease risk behaviour associated with non-disease mortality” they concluded. The British Journal of Psychiatry (2009) 195: 118-125. doi: 10.1192/bjp.bp.108.054866...