title: Personality as a risk factor for illicit opioid use and a protective factor for illicit opioid dependence.
abstract: BACKGROUND
  Most studies investigating the role of personality as a risk factor for the development of opioid dependence compare dependent opioid users with healthy controls who never used heroin. In order to understand the potential protective role of personality, it is crucial to compare illicit opioid users who never became dependent with dependent opioid users.
  
  
  OBJECTIVE
  This study aims to examine the role of personality as a risk factor for opioid use and as a protective factor for the development of opioid dependence.
  
  
  METHODS
  Comparing personality factors between three groups: (1) 161 never-dependent illicit opioid users who have been using illicit opioids but never became opioid dependent; (2) 402 dependent opioid users in methadone maintenance treatment or heroin-assisted treatment; and (3) 135 healthy controls who never used heroin. Personality was assessed with a short version of Cloninger's Temperament and Character Inventory.
  
  
  RESULTS
  Never-dependent opioid users reported more Novelty Seeking and Harm Avoidance and less Self-Directedness and Cooperativeness than healthy controls and more Reward Dependence and Self-Directedness, and less Harm Avoidance than dependent opioid users. Furthermore, never-dependent opioid users reported more Self-Transcendence than both dependent opioid users and healthy controls.
  
  
  CONCLUSIONS
  Never-dependent opioid users may have started to use opioids partly due to their tendency to seek novel and/or spiritual experiences (high Novelty Seeking, high Self-Transcendence) and their tendency to avoid aversive stimuli (high Harm Avoidance), whereas they may have been protected against the development of dependence by their need for social approval (high Reward Dependence) and their self-efficacy (high Self-Directedness).
authors.affiliation: Amsterdam Institute for Addiction Research, Department of Psychiatry, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands; Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands. Electronic address: ezaaijer@gmail.com.
authors.forename: Eline R
authors.initials: ER
authors.lastname: Zaaijer
authors.affiliation: Amsterdam Institute for Addiction Research, Department of Psychiatry, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands.
authors.forename: Jessica
authors.initials: J
authors.lastname: Bruijel
authors.affiliation: Central Committee on the Treatment of Heroin Addicts (CCBH), Utrecht, The Netherlands; Parnassia Addiction Research Centre (PARC, Brijder Addiction Treatment), PO Box 53002, 2505 AA The Hague, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: Blanken
authors.affiliation: Central Committee on the Treatment of Heroin Addicts (CCBH), Utrecht, The Netherlands; Parnassia Addiction Research Centre (PARC, Brijder Addiction Treatment), PO Box 53002, 2505 AA The Hague, The Netherlands.
authors.forename: Vincent
authors.initials: V
authors.lastname: Hendriks
authors.affiliation: Amsterdam Institute for Addiction Research, Department of Psychiatry, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands.
authors.forename: Maarten W J
authors.initials: MW
authors.lastname: Koeter
authors.affiliation: Laboratory of the Biology of Addictive Diseases, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
authors.forename: Mary Jeanne
authors.initials: MJ
authors.lastname: Kreek
authors.affiliation: Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Booij
authors.affiliation: Amsterdam Institute for Addiction Research, Department of Psychiatry, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands.
authors.forename: Anna E
authors.initials: AE
authors.lastname: Goudriaan
authors.affiliation: Central Committee on the Treatment of Heroin Addicts (CCBH), Utrecht, The Netherlands; Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, The Netherlands.
authors.forename: Jan M
authors.initials: JM
authors.lastname: van Ree
authors.affiliation: Amsterdam Institute for Addiction Research, Department of Psychiatry, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands; Central Committee on the Treatment of Heroin Addicts (CCBH), Utrecht, The Netherlands.
authors.forename: Wim
authors.initials: W
authors.lastname: van den Brink
mesh_terms: D000328:Adult; D005260:Female; D040261:Harm Reduction; D006801:Humans; D013287:Illicit Drugs; D008297:Male; D008875:Middle Aged; D009293:Opioid-Related Disorders / Q000175:diagnosis / Q000517:prevention & control* / Q000523:psychology*; D010551:Personality; D010555:Personality Inventory; D065840:Protective Factors; D012201:Reward; D012307:Risk Factors; D013694:Temperament
chemical_list: D013287:Illicit Drugs
keywords: Dependence; Opioid; Personality; Protective factors; Risk factors; TCI