The Adverse Effects of Smoking on Health Outcomes in Bipolar Disorder: A Review and Synthesis of Biological Mechanisms.

Several biological systems are implicated in the neuroprogression of bipolar disorder including but not limited to cytokine levels, oxidative stress markers, monoamine levels, tryptophan catabolite and glutamate-mediated excitotoxicity, microglial activation as well as structural and functional changes. The high rate of smoking behaviour in individuals with bipolar disorder provides the impetus for exploring shared and discrete pathogenetic mechanisms. In addition to contributing to increased mortality, smoking activates several neurobiological effector systems implicated in the progression of bipolar disorder. Here, a narrative review provides evidence and putative mechanisms of comorbid effects of BD, cigarette use, and nicotine dependence, and discusses the clinical implications of these interactions.