Enhanced intensity dependence and aggression history indicate previous regular ecstasy use in abstinent polydrug users

Li Wan, Robyn M. Baldridge, Amanda M. Colby, Matthew S. Stanford

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Intensity dependence is an electrophysiological measure of intra-individual stability of the augmenting/reducing characteristic of N1/ P2 event-related potential amplitudes in response to stimuli of varying intensities. Abstinent ecstasy users typically show enhanced intensity dependence and higher levels of impulsivity and aggression. Enhanced intensity dependence and high impulsivity and aggression levels may be due to damage in the brain's serotonergic neurons as a result of ecstasy use. The present study investigated whether intensity dependence, impulsivity and aggression history can be used as indictors of previous chronic ecstasy usage. Forty-four abstinent polydrug users (8 women; age 19 to 61 years old) were recruited. All participants were currently residents at a local substance abuse facility receiving treatment and had been free of all drugs for a minimum of 21 days. The study found significantly enhanced intensity dependence of tangential dipole source activity and a history of more aggressive behavior in those who had previously been involved in chronic ecstasy use. Intensity dependence of the tangential dipole source and aggressive behavior history correctly identified 73.3% of those who had been regular ecstasy users and 78.3% of those who had not. Overall, 76.3% of the participants were correctly classified.

Original languageEnglish (US)
Pages (from-to)1484-1490
Number of pages7
JournalProgress in Neuro-Psychopharmacology and Biological Psychiatry
Issue number8
StatePublished - Nov 13 2009


  • Aggression
  • Dipole source activity
  • Ecstasy use
  • Impulsive
  • Intensity dependence

ASJC Scopus subject areas

  • Pharmacology
  • Biological Psychiatry


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