Addiction is a complex physiological phenomenon that is intimately linked to the dopamine neurotransmitter system. Neurons in the dopamine system are studded with cannabinoid receptors (like CB1) which explains the addictive properties of cannabinoid substances. However, the interaction between the cannabinoid system and the dopamine system also offers opportunities for cannabinoids in the treatment of Addiction to for instance alcohol, food, nicotine or opioids.
CB1 is the most abundant G-protein coupled receptor in the parts of the brain that are most involved in addictive behavior, suggesting a link. At least one genetic variation/polymorphism in CB1 is linked to increased receptor binding and increased CB1-mediated neuronal activation in the prefrontal cortex (Hutchison et al., 2008). Exposure to alcohol increases activation of the nucleus accumbens, ventromedial prefrontal cortex, orbitofrontal cortex and ventral tegmental area and increases the subjective appreciation of alcohol. Similar linkage to Addiction risk has been reported for the Mu opioid receptor which weakly binds THC and can thus be considered a cannabinoid receptor(Hutchison et al., 2008; Pertwee et al., 2010).
Post-mortem research suggests that although expression is unaffected, CB1 receptors are hyperactive in the caudate nucleus and hypoactive in the cerebellum of alcoholics (Erdozain et al., 2015).
Blocking the reward signal with CB1 antagonists blocks dopaminergic signaling in the nucleus accumbens and decreases alcohol craving and consumption (reference within: Hutchison et al., 2008).
In one study in rats, chronic stimulation of the endocannabinoid system (Anandamide) reduced addictive behavior (cocaine seeking), suggesting a role for the endocannabinoid system in suppressing Addiction (Chauvet et al., 2014).
Chauvet, C., Nicolas, C., Thiriet, N., Lardeux, M.V., Duranti, A., and Solinas, M. (2014). Chronic Stimulation of the Tone of Endogenous Anandamide Reduces Cue- and Stress-Induced Relapse in Rats. Int. J. Neuropsychopharmacol. Off. Sci. J. Coll. Int. Neuropsychopharmacol. CINP.
Erdozain, A.M., Rubio, M., Meana, J.J., Fernández-Ruiz, J., and Callado, L.F. (2015). Altered CB1 receptor coupling to G-proteins in the post-mortem caudate nucleus and cerebellum of alcoholic subjects. J. Psychopharmacol. Oxf. Engl.
Hutchison, K.E., Haughey, H., Niculescu, M., Schacht, J., Kaiser, A., Stitzel, J., Horton, W.J., and Filbey, F. (2008). The incentive salience of alcohol: translating the effects of genetic variant in CNR1. Arch. Gen. Psychiatry 65, 841–850.
Pertwee, R.G., Howlett, A.C., Abood, M.E., Alexander, S.P.H., Di Marzo, V., Elphick, M.R., Greasley, P.J., Hansen, H.S., Kunos, G., Mackie, K., et al. (2010). International Union of Basic and Clinical Pharmacology. LXXIX. cannabinoid receptors and their ligands: beyond CBΌ and CB. Pharmacol. Rev. 62, 588–631.
Pradier, B., Erxlebe, E., Markert, A., and Rácz, I. (2015). Interaction of cannabinoid receptor 2 and social environment modulates chronic alcohol consumption. Behav. Brain Res. 287, 163–171.
In another trial, ad hoc use of CBD was found to reduce cigarette smoking by 40% (Morgan et al., 2013).
Jansma, J.M., van Hell, H.H., Vanderschuren, L.J.M.J., Bossong, M.G., Jager, G., Kahn, R.S., and Ramsey, N.F. (2013). THC reduces the anticipatory nucleus accumbens response to reward in subjects with a nicotine Addiction. Transl. Psychiatry 3, e234.
Morgan, C.J.A., Das, R.K., Joye, A., Curran, H.V., and Kamboj, S.K. (2013). Cannabidiol reduces cigarette consumption in tobacco smokers: preliminary findings. Addict. Behav. 38, 2433–2436.