Impulsivity and attentional bias as predictors of modafinil treatment outcome for retention and drug use in crack-cocaine dependent patients: Results of a randomised controlled trial

J Psychopharmacol. 2016 Jul;30(7):616-26. doi: 10.1177/0269881116645268. Epub 2016 May 4.


Background: High impulsivity and attentional bias are common in cocaine-dependent patients and predict poor treatment outcomes. The pharmacological agent modafinil is studied for its cognitive-enhancing capacities and may therefore improve clinical outcomes in crack-cocaine dependent patients. In this study, we investigated first whether pre-treatment impulsivity and attentional bias predict treatment outcome; next whether the drug modafinil given as an add-on treatment to cognitive behavioural therapy (CBT) improves impulsivity and attentional bias; and last, whether changes in impulsivity and attentional bias are related to improvements in treatment outcome.

Methods: Crack-cocaine dependent outpatients (n = 65) were randomised to 12 weeks CBT plus modafinil (400 mg/day) or only CBT. Self-reported impulsivity was assessed at baseline using the Barratt Impulsiveness Scale. At baseline and Week 12, we assessed inhibitory control as a behavioural measure of impulsivity, in terms of cognitive interference (Stroop task) and response inhibition ('stop-signal task'), and attentional bias with the addiction Stroop task. Clinical outcomes were CBT-retention and crack-cocaine use.

Results: At baseline, self-reported impulsivity predicted better CBT-retention; low self-reported and behavioural impulsivity and attentional bias predicted less crack-cocaine use. Changes in cognitive performance were not modafinil-related, but most likely due to low adherence. Improvements in impulsivity or attentional bias were not associated with CBT-retention nor changes in crack-cocaine use.

Conclusions: Baseline impulsivity and attentional bias predicted clinical outcomes in crack-cocaine dependent patients. There were no firm indications that modafinil reduced impulsivity nor attentional bias in this population. Future studies involving cognitive-enhancing medications should include strategies to optimise adherence, to be better able to evaluate their potential.

Keywords: Adherence; attentional bias; cocaine dependence; cognition; cognitive behavioural therapy; crack cocaine; drug use; impulsivity; modafinil; randomised controlled trial.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Attention / drug effects*
  • Attentional Bias / drug effects*
  • Behavior, Addictive / drug therapy
  • Benzhydryl Compounds / therapeutic use*
  • Cocaine-Related Disorders / drug therapy*
  • Cognitive Behavioral Therapy / methods
  • Crack Cocaine / adverse effects*
  • Female
  • Humans
  • Impulsive Behavior / drug effects*
  • Male
  • Middle Aged
  • Modafinil
  • Nootropic Agents / therapeutic use
  • Stroop Test
  • Treatment Outcome


  • Benzhydryl Compounds
  • Crack Cocaine
  • Nootropic Agents
  • Modafinil