Drug addiction endophenotypes: impulsive versus sensation-seeking personality traits

Abstract

Background: Genetic factors have been implicated in the development of substance abuse disorders, but the role of pre-existing vulnerability in addiction is still poorly understood. Personality traits of impulsivity and sensation-seeking are highly prevalent in chronic drug users and have been linked with an increased risk for substance abuse. However, it has not been clear whether these personality traits are a cause or an effect of stimulant drug dependence.

Method: We compared self-reported levels of impulsivity and sensation-seeking between 30 sibling pairs of stimulant-dependent individuals and their biological brothers/sisters who did not have a significant drug-taking history and 30 unrelated, nondrug-taking control volunteers.

Results: Siblings of chronic stimulant users reported significantly higher levels of trait-impulsivity than control volunteers but did not differ from control volunteers with regard to sensation-seeking traits. Stimulant-dependent individuals reported significantly higher levels of impulsivity and sensation-seeking compared with both their siblings and control volunteers.

Conclusions: These data indicate that impulsivity is a behavioral endophenotype mediating risk for stimulant dependence that may be exacerbated by chronic drug exposure, whereas abnormal sensation-seeking is more likely to be an effect of stimulant drug abuse.

Figure 1

Comparisons between stimulant-dependent individuals, their full biological bothers/sisters, and unrelated healthy control volunteers with regard to (A) impulsive personality traits, as reflected by the Barratt Impulsiveness Scale, Version 11 total score, and (B) sensation-seeking personality traits, as reflected by the Sensation-Seeking Scale Form V total score. (C) The group differences in impulsivity are also reflected on the Barratt Impulsiveness Scale, Version 11 subscales for attentional, motor, and nonplanning impulsivity, and (D) on the Sensation-Seeking Scale Form V subscales for thrill and adventure-seeking, experience-seeking, disinhibition, and boredom susceptibility (note: the asterisks indicate the significant differences). BIS-11, Barratt Impulsiveness Scale, Version 11; SSS-V, Sensation-Seeking Scale Form V.