Effects of impulsivity on executive functions in heroin addicts: an ERP study

Abstract

Objective To investigate the influence of impulsivity on the functions of the conflict monitoring and the conflict resolution process for heroin addicts. Methods 80 heroin addicts were drawn randomly using simple random sampling method and finished Opioid Addiction Severity Inventory(OASI) and Barratt Impulsivity Scale (BIS-11). High impulsivity group(7 females of 22) and low impulsivity group(8 females of 21) were divided according to 27% of the total BIS-11score followed the grouping method in psychometrics. Then the event-related potentials (ERPs) technique with the classical color-word Stroop task was used to reveal the influence of impulsivity on the executive function for heroin addicts. Results (1) The scores of motor impulsivity(23.00±1.73) and no-plan impulsivity(27.77±3.22) were higher in high impulsivity group than those in low impulsivity group(19.31±2.80, 23.38±3.59)(P<0.01); and there was positive correlation between impulsivity and addiction severity(r=0.415, P<0.05). (2) The behavioral data showed significant Stroop interference effects in both groups(P<0.01). (3) ERPs data showed that there were significant incongruent-N450 and SP effects in the low impulsivity group, whereas incongruent N450 and SP effects disappeared in high impulsivity group(Low impulsivity group incongruent vs congruent condition N450: (2.82±3.09)μV vs (4.51±2.77)μV, P<0.05; SP: (3.54±1.25)μV vs (2.84±1.03)μV, P<0.05; High impulsivity group incongruent vs congruent condition N450: (4.98±4.10)μV vs (3.39±3.31)μV, P<0.05; SP: (3.43±3.84)μV vs (4.66±4.53)μV, P<0.05). Conclusion The brain time-interval change of executive function such as the conflict monitoring and the conflict resolution process is influenced by the impulsivity levels of heroin addicts. Key words: Impulsivity; Stroop effect; Executive function; Event-related potentials(ERPs); Heroin addicts