[Electrodermal activity in heroin addicts and patients with methadone and morphine substitution]

In the present investigation we tried to answer the question whether differences between heroin-dependent patients (n = 26, age: M = 24.96, SD = 6.30 years), a methadone substitution group (n = 20, age: M = 30.92, SD = 8.21 years) and a morphine substitution group (n = 20, age: M = 33.25, SD = 4.59 years) and healthy normals (n = 31, age: M = 25.07, SD = 4.62 years) could be found by means of measurement of electrodermal activity (SC, SCR, habituation of the SCR). Concerning "basal" skin conductance reflecting sympathetic activity, no significant differences were obtained. The methadone substitution group showed slight shortened onset latencies (information processing). In the morphine substitution group as compared to the other groups a small increase of the amplitude was observed indicating a slight increase in cognitive emotional intensity of appraisal after presentation of an acoustic stimulus. This small changes could be mediated by adaptation processes of the vegetative nervous system to the opioid, which occur "below" of those neuronal networks connected directly with the emotional stimuli processing. Concerning the speed of habituation no significant differences between the groups could be obtained. This indicates that no psychovegetative attenuation could be observed. The morphine substitution group as compared to the other groups was characterized by a longer persistence and a small increase of the intensity of excitement. However these variables ranged within normal limits and did not reach the level of statistical significance. This could be mediated by the effects of the opioid on the vegetative nervous system.