title: Biased number perception of schematic expressions in abstinent heroin abusers compared to normal controls.
abstract: OBJECTIVE
  Drug-dependent people exhibit biases when evaluating discrete emotional facial expressions. Little is known about how drug abusers process multiple expressions presented simultaneously. The present study investigated the number perception of schematic emotional expressions by abstinent heroin abusers.
  
  
  METHODS
  Eighty-four heroin abstainers with varied lengths of abstinence (short-term, mid-term, and long-term) and twenty healthy controls were examined. A method of limits was deployed to obtain estimates (points of subjective equality) of perceived numbers of schematic faces (expressing positive, neutral, or negative emotion).
  
  
  RESULTS
  Major results include the following: 1) heroin-abstinent participants showed significantly lower points of subjective equality for negative and neutral faces, but not for positive faces, compared to control participants; 2) heroin-abstinent participants showed lower points of subjective equality for negative faces and higher ones for positive faces when compared to neutral faces, while no such differences were found in control participants.
  
  
  CONCLUSIONS
  Heroin abusers demonstrate an exaggerated perception of number when exposed to negative expressions, even after a period of abstinence as long as 10 months. In addition, the current results could also reflect an underestimated perception of number during exposure to positive expressions and a heightened baseline for neutral expressions, or the attribution of negative valence to neutral expressions by heroin abusers.
authors: Department of Psychology and Behavioral Sciences, Zhejiang University, Hang Zhou 310028, China.
authors: Meng
authors: M
authors: Zhang
authors: Haiyan
authors: H
authors: Zhu
authors: Xinyu
authors: X
authors: Li
authors: Rende
authors: R
authors: Shui
authors: Mowei
authors: M
authors: Shen
mesh_terms: D000328:Adult; D004644:Emotions; D005149:Facial Expression; D005260:Female; D003932:Heroin / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008433:Mathematics; D010364:Pattern Recognition, Visual; D010468:Perceptual Disorders / Q000209:etiology*; D010775:Photic Stimulation; D013375:Substance Withdrawal Syndrome / Q000150:complications*; D013997:Time Factors; D055815:Young Adult
chemical_list: D003932:Heroin