TASTE-REACTIVITY AND ODOR-REACTIVITY IN HEROIN-ADDICTS

Opiates in general, and heroin in particular, are known to induce comp ulsive drug-seeking and drug-taking behavior. Addiction is accompanied by psychobiological processes which may distort perception of sensory stimuli. Gustatory and olfactory stimuli are hedonically polarized an d therefore most appropriate for the assessment of the organism's reac tivity to ''useful'' and ''harmful'' chemosensory events. Previous stu dies revealed that psychophysical self-estimates and reflectory facial expressions mirror with comparable reliability the hedonics of the pe rceived taste and odor sensations. In the present study both cognitive verbal and reflectory facial expressions of a group of: a) heroin add icts were recorded and compared to those of a group of b) detoxified f ormer addicts and to c) a group Of matching controls. Results show tha t all three groups differentiate between pleasant, indifferent and ave rsive tastes and odors. Active addicts estimated sweet taste and savor y smells as being somewhat more pleasant, and bitter and sour tastes a nd a putrid odor as less unpleasant than did the other two groups. The reflectory facial displays of addicts were less expressive and discri minative than those of the two other groups. Taste-and odor-induced fa cial displays are known to be controlled primarily by the brainstem. T he findings indicate that heroin-addiction affects brain-mechanisms, w hich mirror taste-and odor-hedonics. Modulation of the phylogeneticall y ancient, sensory-motor coordinations was found to be of a different pattern than that of the cortically-controlled cognitive reactions.