Why are Antidepressant Drugs Effective Smoking Cessation Aids?

Abstract

BackgroundBefore the advent of varenicline, antidepressant drugs were reported to exhibit better clinical efficacy than nicotine replacement therapy as smoking cessation aids. The most studied is bupropion, a clinically-effective antidepressant, the first to be marketed throughout Europe for smoking cessation. Since depression and tobacco smoking have a high incidence of co-occurrence, this would implicate an underlying link between these two conditions. If this correlation can be confirmed, then by treating one condition the related state would also be treated.ObjectivesThis review article will evaluate the various theories relating to the use of antidepressant drugs as smoking cessation aids and the underlying mechanisms link tobacco smoking and depression to explain the action of antidepressants in smoking cessation. One plausible theory of self-medication which proposes that people take nicotine to treat their own depressive symptoms and the affective withdrawal symptoms seen with abstinence from the drug. If the depression can instead be treated with antidepressants, then they may stop smoking altogether. Another theory is that the neurobiological pathways underlying smoking and depression may be similar. By targeting the pathways of depression in the brain, antidepressants would also treat the pathways affected by smoking and ease nicotine cravings and withdrawal. The role of genetic variation predisposing an individual to depression and initiation of tobacco smoking has also been discussed as a potential link between the two conditions. Such variation could either occur within the neurobiological pathways involved in both disorders or it could lead to an individual being depressed and self-medicating with nicotine.

A microbial metabolite synergizes with endogenous serotonin to triggerC. elegansreproductive behavior

“…Accordingly, a large number of psychiatric diseases are treated with small-molecule therapeutics that agonize or antagonize serotonin signaling (1,2). Small molecules that boost endogenous serotonin signaling, such as inhibitors of serotonin catabolism or reuptake and serotonin receptor agonists, are used to treat major depression, anxiety disorders, and alcohol and nicotine addiction (3)(4)(5). Compounds that inhibit serotonin receptors are also clinically important; many antipsychotics are potent antagonists of a subset of G protein-coupled serotonin receptors.…”

Editorial: Nicotine and the Nicotinic Cholinergic System in Health and Disease

“…Furthermore, the involvement of nAChRs in various pathological conditions such as cognitive disorders, anxiety, depression, Alzheimer’s and Parkinson’s disease, pain and epilepsy can be elucidated using beneficially modified animal models [ 1 ]. Along the same lines, drugs can be developed that target nAChR for the treatment of several disorders, including Shizophrenia and some cognitive disorders [ 2 , 6 , 7 ].…”

“…Cognitive enhancing effects also contribute to difficulties in smoking cessation [ 7 ]. Pharmacological agents that enhance cognition may help smokers quit smoking [ 6 , 7 ]. Selective α7 nAChR agonists may be used to treat cognitive deficits in Schizophrenia, Alzheimer’s and ADHD as well as in smoking cessation [ 7 ].…”

“…Liu & Li [ 2 ] elaborate on genetic associations: SNPs within genes encoding nAChR subunits are associated with phenotypes of nicotine addiction and smoking cessation. Brain regions associated with nicotine addiction are discussed and the relationship between psychiatric diseases and tobacco addiction is discussed with evidence from preclinical and clinical studies [ 6 ]. Shoaib & Buhidma [ 6 ] provide a comprehensive account of the use of antidepressant drugs in smoking cessation.…”

“…Brain regions associated with nicotine addiction are discussed and the relationship between psychiatric diseases and tobacco addiction is discussed with evidence from preclinical and clinical studies [ 6 ]. Shoaib & Buhidma [ 6 ] provide a comprehensive account of the use of antidepressant drugs in smoking cessation. The authors discuss the possible underlying link between depression and tobacco smoking and point to the importance of targeting more than one pathway in developing effective smoking cessation strategies.…”