Neuropsychologic deficit in chronic heroin abusers

Neurological consequences of chronic heroin exposure are poorly known. 38 m ale patients with current heroin abuse or dependence were examined in withd rawal period that lasted more than 10 days, and were compared with 19 healt hy controls. Wisconsin Card Sorting Test (WCST), "Delayed Alternation" Test (DAT), "Tower of London" Test (TLT), Russian version of WAIS (1995) were u sed. Patients were medicated and medication status was evaluated by psychom otor speed level. Patients with the duration of daily heroin abuse more tha n 1,5 years performed significantly less effectively TLT solutions as compa red with the healthy controls (after Bonferroni correction, p=0001). Patien ts with shorter duration of daily heroin abuse had a trend to perform TLT s olutions poorer as compared to healthy controls and better than group with longer duration (after Bonferroni correction, p=0,07 and 0,08). Three group s did not differ by WCST and DAT significantly, and general intelligence wa s in normal range in three groups. Multiple regression analysis confirmed s ignificant influence of daily heroin abuse duration on TLT performance effi ciency in our population (P=-0,426, p<0,05) without effect of age, educatio n, IQ, dosage of heroin per day, withdrawal duration and current medication status (psychomotor speed level). Perseverative responses on DAT were sign ificantly related to daily heroin dosages before treatment (<beta>=0,405, p <0,05) and negatively correlated with the withdrawal duration. These data g ive grounds to suppose, that chronic heroin exposure impairs planning funct ions of prefrontal cortex (TLT), that can be explained by cumulative neuron al damages of prefrontal cortex and VTA dopamine neurons. That was demonstr ated in experimental and morphological studies of opiate addicts who died a fter opiate overdose. Large doses of heroin can induce more extensive funct ional impairment with possible involvement of orbit frontal cortex. The lat ter deficit may be partially reversible during short-term withdrawal.