Do reward-processing deficits in schizophrenia-spectrum disorders promote cannabis use? An investigation of physiological response to natural rewards and drug cues

J Psychiatry Neurosci. 2014 Sep;39(5):339-47. doi: 10.1503/jpn.130207.

Abstract

Background: Dysfunctional reward processing is present in individuals with schizophrenia-spectrum disorders (SSD) and may confer vulnerability to addiction. Our objective was to identify a deficit in patients with SSD on response to rewarding stimuli and determine whether this deficit predicts cannabis use.

Methods: We divided a group of patients with SSD and nonpsychotic controls into cannabis users and nonusers. Response to emotional and cannabis-associated visual stimuli was assessed using self-report, event-related potentials (using the late positive potential [LPP]), facial electromyography and skin-conductance response.

Results: Our sample comprised 35 patients with SSD and 35 nonpsychotic controls. Compared with controls, the patients with SSD showed blunted LPP response to pleasant stimuli (p = 0.003). Across measures, cannabis-using controls showed greater response to pleasant stimuli than to cannabis stimuli whereas cannabis-using patients showed little bias toward pleasant stimuli. Reduced LPP response to pleasant stimuli was predictive of more frequent subsequent cannabis use (β = -0.24, p = 0.034).

Limitations: It is not clear if the deficit associated with cannabis use is specific to rewarding stimuli or nonspecific to any kind of emotionally salient stimuli.

Conclusion: The LPP captures a reward-processing deficit in patients with SSD and shows potential as a biomarker for identifying patients at risk of heavy cannabis use.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / physiopathology*
  • Cannabis*
  • Cues*
  • Electroencephalography
  • Electromyography
  • Evoked Potentials, Visual
  • Facial Muscles / physiopathology
  • Galvanic Skin Response
  • Heterosexuality
  • Humans
  • Male
  • Marijuana Abuse / complications
  • Marijuana Abuse / diagnosis
  • Marijuana Abuse / physiopathology
  • Marijuana Abuse / psychology
  • Neuropsychological Tests
  • Photic Stimulation
  • Prognosis
  • Psychotic Disorders / complications
  • Psychotic Disorders / physiopathology*
  • Psychotic Disorders / psychology*
  • Reward*
  • Schizophrenic Psychology*
  • Tobacco Use Disorder / complications
  • Tobacco Use Disorder / physiopathology
  • Tobacco Use Disorder / psychology
  • Visual Perception / physiology*