High impulsivity in rats predicts amphetamine conditioned place preference

Stimulants such as d-amphetamine (AMPH) are used commonly to treat attention-deficit hyperactivity disorder (ADHD), but concerns have been raised regarding the use of AMPH due to its reinforcing and potentially addictive properties. The current study examined if individual differences in impulsive choice predict AMPH-induced hyperactivity and conditioned place preference (CPP). Rats were first tested in delay discounting using an adjusting delay procedure to measure impulsive choice and then were subsequently tested for AMPH CPP. High impulsive (Hil) and low impulsive (Lol) rats were conditioned across four sessions with 0.1, 0.5, or 1.5 mg/kg of AMPH. AMPH increased locomotor activity for Hil and Lol rats following 0.5 mg/kg but failed to increase activity following 0.1 and 1.5 mg/kg. CPP was established for Hil rats with both 0.5 and 1.5 mg/kg of AMPH, whereas Lot rats did not develop CPP following any dose of AMPH; Hil and Lol groups differed significantly following 0.5 mg/kg of AMPH. These results indicate that Hil rats are more sensitive to the rewarding effects of AMPH compared to Lot rats, which is consistent with research showing that high impulsive individuals may be more vulnerable to stimulant abuse. (C) 2011 Published by Elsevier Inc.