Impact of Δ9-tetrahydrocannabinol (THC) and synthetic “spice” cannabinoids on nicotine use and abuse

Tobacco and cannabis are two of the most used substances of abuse. The emergence of nicotine e-cigarettes and THC vaping, along with legalization of cannabis in many regions, has resulted in an increased prevalence among many populations. It has also been well documented that tobacco and cannabis are often co-used by individuals, which may induce interactive effects at the cellular level given overlapping expression patterns of receptor systems in the brain. This chapter will begin by providing an overview of the prevalence of tobacco/nicotine and cannabis/THC use among varying populations, with a subsequent focus on patterns of co-use. In addition to the plant-derived cannabinoid, THC, discussion will focus on the emergence of synthetic cannabinoids, a class of chemical compounds that include “spice.” Next, we will consider the implications of single and co-use on cognition and drug-taking behaviors with data derived from both human and animal models. The findings reviewed herein provide a comprehensive analysis of the impact of nicotine and cannabinoid single and co-use on drug reinforcement and associated behaviors, with further considerations for therapeutic development to treat drug dependence.