Cannabidiol treatment reduces the motivation to self-administer methamphetamine and methamphetamine-primed relapse in rats

BACKGROUND:: Methamphetamine is an addictive stimulant that can cause many adverse physical, psychological and psychosocial effects. Preliminary evidence shows cannabidiol, a non-intoxicating constituent of the cannabis plant, may have efficacy in treating opioid and nicotine dependence. However, no study has yet examined whether cannabidiol treatment might impact on methamphetamine addiction. AIMS:: The current study investigated whether cannabidiol administration reduces the motivation to self-administer methamphetamine and relapse to methamphetamine-seeking behavior following abstinence. METHODS:: Thirty-two male Sprague Dawley rats with implanted jugular vein catheters were initially trained to self-administer methamphetamine via lever press during two-hour sessions on a fixed ratio 1 schedule of reinforcement. Rats in experiment 1 ( n=16) then advanced to a progressive ratio reinforcement schedule to examine the effects of cannabidiol (0, 20, 40, and 80 mg/kg intraperitoneal) on motivation to self-administer methamphetamine. Rats in experiment 2 ( n=16) were tested for cannabidiol effects on methamphetamine-primed reinstatement following extinction. RESULTS:: Cannabidiol (80 mg/kg, but not 40 mg/kg, or 20 mg/kg) reduced the motivation to self-administer methamphetamine and attenuated methamphetamine-primed relapse to methamphetamine-seeking behavior after extinction. CONCLUSION:: This is the first demonstration that cannabidiol can reduce the motivation to seek and consume methamphetamine, and suggests that cannabidiol might be worth trialing as a novel pharmacotherapy for methamphetamine dependence.