Functional changes of the reward system underlie blunted response to social gaze in cocaine users.
Social interaction deficits in drug users likely impede treatment, increase the burden of the affected families, and consequently contribute to the high costs for society associated with addiction. Despite its significance, the neural basis of altered social interaction in drug users is currently unknown. Therefore, we investigated basal social gaze behavior in cocaine users by applying behavioral, psychophysiological, and functional brain-imaging methods. In study I, 80 regular cocaine users and 63 healthy controls completed an interactive paradigm in which the participants' gaze was recorded by an eye-tracking device that controlled the gaze of an anthropomorphic virtual character. Valence ratings of different eye-contact conditions revealed that cocaine users show diminished emotional engagement in social interaction, which was also supported by reduced pupil responses. Study II investigated the neural underpinnings of changes in social reward processing observed in study I. Sixteen cocaine users and 16 controls completed a similar interaction paradigm as used in study I while undergoing functional magnetic resonance imaging. In response to social interaction, cocaine users displayed decreased activation of the medial orbitofrontal cortex, a key region of reward processing. Moreover, blunted activation of the medial orbitofrontal cortex was significantly correlated with a decreased social network size, reflecting problems in real-life social behavior because of reduced social reward. In conclusion, basic social interaction deficits in cocaine users as observed here may arise from altered social reward processing. Consequently, these results point to the importance of reinstatement of social reward in the treatment of stimulant addiction.
Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric Hospital, University of Zurich, 8032 Zurich, Switzerland.
Katrin H
KH
Preller
Marcus
M
Herdener
Leonhard
L
Schilbach
Philipp
P
Stämpfli
Lea M
LM
Hulka
Matthias
M
Vonmoos
Nina
N
Ingold
Kai
K
Vogeley
Philippe N
PN
Tobler
Erich
E
Seifritz
Boris B
BB
Quednow
D000328:Adult; D019970:Cocaine-Related Disorders / Q000150:complications* / Q000503:physiopathology* / Q000628:therapy; D005133:Eye Movements / Q000502:physiology; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D007398:Interpersonal Relations; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D059906:Neuroimaging / Q000379:methods; D012201:Reward; D012920:Social Behavior Disorders / Q000209:etiology* / Q000503:physiopathology*; D013557:Switzerland
dopamine; joint attention; reinforcement; social cognition; social functioning