Cannabis and the Use of Amphetamine-Like Substances

Cannabis is the most widely consumed illicit drug worldwide, with a global use estimated between 2.9 and 4.3% of the population aged 16–64. Its consumption is frequently associated with concurrent use of other psychoactive compounds such as alcohol, cocaine, and amphetamine-like substances (ie, amphetamines, methamphetamine, and 3,4-methylenedioxymethamphetamine). Recently, surveys and self-reports have shown that new psychoactive substances, such as cathinones and their derivatives, are often coabused with cannabis. The psychostimulant and rewarding properties of amphetamine-like substances are due to their ability to enhance dopaminergic neuron activity in the mesolimbic pathway by raising the levels of dopamine, the main neurotransmitter involved in reward circuitry. The combination of cannabis with these drugs enhances the subjective drug effects, and counteracts the dysphoric symptoms of ecstasy and “coming down” from methamphetamine, thus improving and mellowing the drug experience. In this chapter we describe the molecular pharmacology and pharmacological/neurobiological effects induced by amphetamine-like substances in combination with cannabis.