title: Psychopharmacology of Tobacco and Alcohol Comorbidity: a Review of Current Evidence.
abstract: OBJECTIVE
  Comorbidity of alcohol and tobacco use is highly prevalent and may exacerbate the health effects of either substance alone. However, the mechanisms underlying this comorbidity are not well understood. This review will examine the evidence for shared neurobiological mechanisms of alcohol and nicotine comorbidity and experimental studies of the behavioural consequences of these interactions.
  
  
  RESULTS
  Studies examining the shared neurobiology of alcohol and nicotine have identified two main mechanisms of comorbidity: (1) cross-reinforcement via the mesolimbic dopamine pathway and (2) cross-tolerance via shared genetic and nAChR interaction. Animal and human psychopharmacological studies demonstrate support for these two mechanisms of comorbidity.
  
  
  CONCLUSIONS
  Human behavioural studies indicate that (1) alcohol and tobacco potentiate each other's rewarding effects and (2) nicotine reduces the sedative and intoxication effects of alcohol. Together, these findings provide a strong evidence base to support the role of the cross-reinforcement and cross-tolerance as mechanisms underlying the comorbidity of alcohol and tobacco use. Methodological concerns in the literature and recommendations for future studies are discussed alongside implications for treatment of comorbid alcohol and tobacco use.
authors.affiliation: Department of Psychology, University of Bath, 10 West, Bath, BA2 7AY UK.|UK Centre for Tobacco and Alcohol Studies, Bath, UK.
authors.forename: Sally
authors.initials: S
authors.lastname: Adams
keywords: Alcohol; Comorbidity; Cross-reinforcement; Cross-tolerance; Nicotine; Psychopharmacology