THC like other drugs of abuse, releases DA in the mesocortico-limbic regions of animal brains [17–19]. PET brain imaging studies in healthy human volunteers provide inconsistent evidence for this action in humans. One study showed modest THC-induced dopamine release in the ventral striatum and dorsal putamen using [11C] raclopride [20]. Another study found no significant effect of THC on [11C] raclopride binding, although THC markedly increased psychosis-like symptoms [21]. A subsequent study using the same methodology found significant decreases in frontal and temporal lobe [11C] raclopride binding after THC challenges, but no changes in the striatum, which is also part of the dopamine reward pathway [22]. Decreased frontal lobe binding significantly correlated with catechol-O-methyltransferase (COMT) status. Therefore, medications that target the brain dopamine reward system may have a role in the treatment of cannabis dependence, as they may for other drugs of abuse.
