Parallels between Gambling and Amphetamine Reinforcement in Pathological Gamblers and Healthy Controls and the Role of Sensitization

Pathological gambling is a serious disorder with lifetime prevalence between 1.1-3.5%. Evidence suggests commonalities in the neurochemical basis of pathological gambling and psychostimulant addiction. However, parallel effects of gambling and a stimulant drug have not been assessed in the same subjects. This study employed a cross-priming strategy in which 12 male pathological gamblers and 11 male controls were exposed to a 15-minute slot machine game and d-amphetamine (0.4 mg/kg). Subjective, cognitive, electrophysiological, and physiological responses were assessed. Gamblers reported greater desire to gamble after both reinforcers, when baseline motivation was controlled. Conversely, gamblers exhibited diminished cardiovascular response to amphetamine. Gamblers also exhibited decreased pre-pulse inhibition (impaired sensorimotor gating), and deficits on this index predicted greater post-amphetamine desire to gamble and decreased heart rate response to the dose. Results are consistent with possible dopaminergic sensitization in pathological gamblers, but also suggest that central noradrenergic receptor deficits contribute importantly to these effects.