A laboratory study found that sensation seeking related to amphetamine self-administration, while a separate impulsivity dimension did not show the same relationship. Treating the combined personality scale as a single measure would obscure that distinction.
Forty healthy emerging adults were recruited across combinations of high and low sensation seeking and impulsivity. The design aimed to examine these dimensions independently, using components of the Zuckerman–Kuhlman Personality Questionnaire.
Participants completed double-blind, placebo-controlled blocks with a sample day and a subsequent self-administration day. On sample days, eight capsules delivered total d-amphetamine doses of zero, 8 or 16 mg. On self-administration days, participants could work on a progressively demanding task to earn capsules matching the previously sampled condition.
Sensation seeking was associated with capsules earned, and the association in the 16 mg sample-dose condition differed significantly from placebo. The corresponding comparison for the 8 mg condition was marginal and did not reach significance at p = 0.06.
The impulsivity component was not significantly associated with capsules earned. Subjective ratings also involved dose- and time-dependent patterns, rather than one uniform relationship with impulsivity. The evidence therefore supports distinguishing desire for novel experiences from the particular rash-action tendency captured by this questionnaire component.
A study using a broad impulsivity score might report a relationship driven largely by its sensation-seeking items. Another study using a different instrument could produce a different result without measuring an identical trait. The present recruitment strategy helped separate components, but did not reproduce the population’s natural distribution of those traits.
The sample was small, dosing was oral, and the tested doses and laboratory opportunities restrict generalization. Working for capsules is an experimental reinforcement measure, not a diagnosis of dependence or proof of future misuse. It also does not measure cognition, drug concentration or driving impairment.
Read our analysis of a separate high-versus-low sensation-seeking reinforcement experiment.
Individual Differences in the Reinforcing and Subjective Effects of d-Amphetamine: Dimensions of Impulsivity. doi:10.1037/pha0000095.