NEUROPSYCNOLOGICAL AND NEUROPHYSIOLOGICAL EVALUATION DURING METHADONE AND BUPRENORPHINE MAINTANCE TREATMENT

Abstract

Abstract:The treatment of opioid dependence with methadone and buprenorphine is equally effective with both drugs in terms of discontinuation of drug use. However, when choosing the drug, many other factors also participate. For example, buprenorphine is known as a drug that gives a "clear head" in contrast to methadone, so it is good for people who are active, students, or are engaged in intellectual work. The aim of this study is to determine if there is a difference in neuropsychological and neurophysiological functioning in individuals treated with methadone versus people who are on buprenorphine treatment. Material and Methods. The study includes a total of 20 respondents, 10 people involved in the methadone maintenance program and 10 people involved in the buprenorphine maintenance program. Patients with co-morbid psychiatric disorders and that who used other psychoactive substances than therapy were excluded. We used non-standardized questionnaire for demographic characteristics and substance use history of the respondents. Wechsler Adult Intelligence Scale for the Macedonian population was used for neuropsychological evaluation. We used 19 channel quantitative electroencephalography (QEEG) for neurophysiological evaluation. Spectral analysis of EEG signals using FFT was done. Absolute and relative power of different brain frequency bands (delta, theta, alpha, beta 1 and beta 2) and corresponding peak frequency of different brain frequency bands were analyzed in several scalp position: Fz, Cz, Pz. 10 healthy subjects were used as a control group. ANOVA, T test and Bonferroni statistical methods were used for the statistical analysis. Results. Neuropsychological results indicate relatively well-informed and efficient use of knowledge gained with the ability to focus attention and maintain concentration. They have developed associative thinking, logical arithmetic and abstract thinking with a decline in quality and the way of thinking function in terms of balance and efficiency in defining terms - weaker precision, flexibility and reduced cultivation and speed of mental response. In an abstract and flexible thinking, they are less effective, they lack perseverance, precision and stability. The manipulative abilities and the speed of the psychomotor reaction in the problem situations have been reduced. Both groups have the highest attainment of ability in solving social problems (interaction and manipulation in their own benefit). The methadone maintained group showed higher level of mental deterioration (M=10,45), but still they were not significantly different compared to buprenorphine(M=5.22). Neuropsysiological results obtained with QEEG showed statistical significant differences in relative power of alfa amplitude in Fz, Cz and Pz with the lowest amplitude in methadone group, statistical significant differences in relative power of theta amplitude between methadone group and controls, but not between buprenorphine and methadone group, with the lowest theta amplitude in the methadone group. There is statistical significant differences in absolute and relative power of beta 1 (13- 21 Hz) peak frequency in Fz, but not at Cz and Pz between methadone group and controls with the higher beta1 peak frequency in methadone group and equal beta 1 peak frequency in buprenorphine group and controls.

Conclusions. Neuropsychologically there are not significantly differences in both groups regarding cognitive functions but the average score of mental deterioration is bigger in methadone group compared with buprenorphine group. Neurophysiologically using QEEG results it is shown that although there are not significant differences in the bioelectrical brain activity between methadone and buprenorphine group, there are significant differences in bioelectrical cortical activity between methadone group and the controls, but not between buprenorphine group and the controls. The results suggest preserved bioelectrical cortical brain activity in buprenorphine group. Still, further investigations with larger number of participants are needed for reproducible results.