[Personality changes in opioid-dependent subjects in a methadone maintenance treatment program]. / Changements psychologiques au cours d'un traitement de substitution de méthadone, mesurés par l'Inventaire de Personnalité d'Eysenck.

Personality disorders and particularly antisocial personality disorders (APD) are quite frequent in opioid-dependent subjects. They show various personality traits: high neuroticism, high impulsivity, higher extraversion than the general population. Previous studies have reported that some but not all personality traits improved with treatment. In a previous study, we found a low rate of APD in a French population of opioid-dependent subjects. For this reason, we evaluated personality traits at intake and during maintenance treatment with methadone. Methods - The form A of the Eysenck Personality Inventory (EPI) was given to opioid addicts at intake and after 6 and 12 months of methadone treatment. Results - 134 subjects (96 males and 38 females) took the test at intake, 60 completed 12 months of treatment. After 12 months, the EPI Neuroticism (N) and the Extraversion-introversion (E) scale scores decreased significantly. The N score improved in the first 6 months, while the E score improved only during the second 6 months of treatment. Compared to a reference group of French normal controls, male and female opioid addicts showed high N and E scores. Demographic data and EPI scores of patients who stayed in treatment for 12 months did not differ significantly from those of dropouts (n=23). Patients with a history of suicide attempts (SA) started to use heroin at an earlier age and they showed a higher E score and a tendency for a higher N score at intake. Discussion - The two personality dimensions of the EPI changed during MMT, and the N score converged towards the score of normal controls. Opioid addicts differ from normal controls mostly in their N score. The EPI did not help to differentiate 12-month completers from dropouts. Higher E scores in patients with an SA history might reflect a higher impulsivity, which has been linked to suicidality in other patient groups.

[The impact of substitution treatment by methadone among opiate-dependent subjects evaluated by Addiction Severity Index and by urine tests]. / Impact d'un traitement de substitution par méthadone sur des sujets dépendants aux opiacés évalué par l'Addiction Severity Index et des contrôles urinaires.

Methadone maintenance treatment (MMT) has been evaluated in the United States and in a few other countries. MMT has been developed in France since 1995, and over 5 000 patients receive this treatment. However no French study has yet been published on the efficacy of MMT as assessed by a validated scale. Retention in treatment for one year has been considered as a threshold to define maintenance of treatment benefits after discharge from a methadone program; determination of retention predictors is important. Over a three year period, we evaluated patients at admission and during treatment using the Addiction Severity Index (ASI), and urine drug screening was performed weekly; 95 patients (66 males and 29 females) were evaluated at intake. Their mean age was 30.2 5.5, and they had used opioids for a mean of 10.6 5.7 years. Their ASI severity scores for drugs were over 5, showing a clear need for treatment. Female patients differed from males only in the employment-finances ASI score; 43 patients completed at least one year of treatment, after which their drug and legal composite scores significantly improved. No significant changes in their consumption of cocaine, alcohol, benzodiazepines or cannabis were found, but they smoked fewer cigarettes at 12 months. Demographics, ASI severity scores, and history of suicide attempts did not differentiate one-year completers from dropouts (n=16). However, dropouts had used more buprenorphine and less methadone in the 30 days preceding their admission, and they received a lower dose of methadone during treatment. Our population is comparable to other French MMT populations; they enter treatment after a long history of opioid dependence. The improvement found on the ASI composite scores is also similar to the improvement described in other international studies. Dropouts in our study seem to be more treatment-resistant patients, in the sense that they had used more buprenorphine before intake and were not stabilized with it; and they may have had a more negative attitude towards methadone.

Chronic but not acute antidepressants interfere with serotonin (5-HT1B) receptors.

Eight days of isolation induced in mice a social behavioral deficit responsive to the serotonin agonists, TFMPP (1-(m-trifluoromethylphenyl)piperazine), m-CPP (1-(3-chlorophenyl)piperazine), RU 24969. These drugs are not specific for one subtype of serotonin receptors but share the property of being able to stimulate 5-HT1B receptors. They exert their effects in this test through this receptor. Fluoxetine and phenelzine were behaviorally inactive and did not impair the TFMPP effect when given acutely. On the contrary, the chronic administration of these two antidepressant drugs significantly antagonized the TFMPP effect. These results demonstrate a link between two antidepressant drugs and a function of 5-HT1B receptors. The lack of effect of acute versus chronic treatments suggests the involvement of 5-HT1B receptors in the therapeutic effect of these drugs.

Benzodiazepines impair a behavioral effect induced by stimulation of 5-HT1B receptors.

Seven days of isolation induce in mice a social behavioral deficit (decrease in escape attempts) reversed by TFMPP acting through activation of 5-HT1B receptors. The present experiments were performed to investigate the interaction between tranquillizing drugs and one aspect of the serotonergic functioning through the TFMPP-induced increase in escape attempts. The benzodiazepines diazepam, alprazolam, triazolam and chlordiazepoxide impaired significantly TFMPP-induced increase in escape attempts at behaviorally inactive doses. Buspirone opposed TFMPP effect, but the active doses 4 and 16 mg/kg alone decreased the number of escape attempts. ICS 205-930 in a large dose range (0.001-1 mg/kg) modified neither the number of escape attempts nor the increase induced by TFMPP. Chronic (11 days) treatment with buspirone (16 mg/kg) or ICS 205-930 (1 mg/kg) modified neither the number of escape attempts of isolated mice nor the increase induced by TFMPP. These results suggest that tranquillizing drugs of the benzodiazepines group, but not of other groups, interact with the 5-HT1B receptors; they add to the knowledge of relations between benzodiazepines and serotonin by specifying the involvement of 5-HT1B receptors.

Increase in the isolation-induced social behavioural deficit by agonists at 5-HT1A receptors.

The effect of 5-HT1A agonists was studied in the isolation-induced social behavioural deficit test. The drugs 8-OH-DPAT (0.125 mg/kg), buspirone (16 mg/kg) and ipsapirone (8 mg/kg) further increased the deficit. Unlike 8-OH-DPAT, the other two drugs may act non-specifically since they reduced spontaneous motor activity at 16 mg/kg, as measured in an activity meter. In addition, 8-OH-DPAT (0.25 mg/kg), buspirone (8 mg/kg) and ipsapirone (8 mg/kg) decreased exploratory activity in the open-field test. Since the smallest active doses were very close in the behavioural deficit and in the open-field tests, it is suggested that a common phenomenon, increased emotionality or reactivity, sustained both these reductions in activity. The increase in the behavioural deficit induced by 8-OH-DPAT, was likely to have resulted from stimulation of 5-HT1A receptors, since it was impaired by pretreatment with penbutolol, a beta-adrenergic-blocking drug, also known to bind to 5-HT1 receptors. Since it was previously shown that the behavioural deficit was reduced by agonists at 5-HT1B receptors, it is proposed that the behavioural inhibition, resulting from an isolation-induced increase in reactivity is bi-directionally modulated by serotonergic drugs, where 5-HT1A agonists increase and 5-HT1B agonists decrease this inhibition.