Although the efficacy of methadone maintenance treatment (MMT) in opioid dependence disorder has been well established, the influence of methadone pharmacokinetics in dose requirement and clinical outcome remains controversial. The aim of this study is to analyze methadone dosage in responder and nonresponder patients considering pharmacogenetic and pharmacokinetic factors that may contribute to dosage adequacy. Opioid dependence patients (meeting Diagnostic and Statistical Manual of Mental Disorders, [4^th Edition] criteria) from a MMT community program were recruited. Patients were clinically assessed and blood samples were obtained to determine plasma concentrations of (R,S)-, (R) and (S)- methadone and to study allelic variants of genes encoding CYP3A5, CYP2D6, CYP2B6, CYP2C9, CYP2C19, and P-glycoprotein. Responders and nonresponders were defined by illicit opioid consumption detected in random urinalysis. The final sample consisted in 105 opioid dependent patients of Caucasian origin. Responder patients received higher doses of methadone and have been included into treatment for a longer period. No differences were found in terms of genotype frequencies between groups. Only CYP2D6 metabolizing phenotype differences were found in outcome status, methadone dose requirements, and plasma concentrations, being higher in the ultrarapid metabolizers. No other differences were found between phenotype and responder status, methadone dose requirements, neither in methadone plasma concentrations. Pharmacokinetic factors could explain some but not all differences in MMT outcome and methadone dose requirements.

During the 1980s, Spain had very strict laws limiting access to opioid agonist maintenance treatment (OAMT). Because of this, mortality among people who used illicit opioids and other illicit drugs was high. Spain was also the European country with the highest number of cases of acquired immunodeficiency syndrome transmitted through illicit drug injection. The rapid spread of human immunodeficiency virus (HIV) infection among people using heroin led to a shift from a drug-free approach to the treatment of opioid dependence to one focused on harm reduction. A substantial change in legislation made it possible to meet public health needs and offer OAMT as part of harm reduction programmes in the public health system, including prisons. Legislative changes were made throughout the country, although at a different pace in different regions. Legal changes facilitated the expansion of OAMT, which has achieved a coverage of 60%. A parallel reduction in the annual incidence of HIV infection has been reported. Reductions in morbidity and mortality and improved health-related quality of life have been described in patients undergoing OAMT. The treatment of opioid dependence has been more heavily influenced by moral concepts and prejudices that hinder legislation and interfere with the implementation of OAMT than by scientific evidence. To fulfil public health needs, OAMT should be integrated in harm reduction programmes offered primarily in public facilities, including prisons. Longitudinal studies are needed to detect unmet needs and evaluate programme impact and suitability.

This study examined the relationship between the personality profile of a sample of cocaine users and the presence of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) diagnoses and the severity of substance use. A total of 120 participants (46 women, mean age: 23.8 years) from nonclinical settings in Barcelona, Spain, 2003-2006, were assessed using the Psychiatric Research Interview for Substance and Mental Disorders (PRISM) and the Temperament and Character Inventory-Revised version (TCI-R). Most of the participants had completed more than primary education, nearly half of them were employed, one third lived with parents, and near a quarter had some criminal record. Snorting was the main route of cocaine administration. They were using a mean of 1.82 substances. Cocaine users with low Self-Directedness, low Cooperativeness, and high Self-Transcendence scores in the TCI-R, with high severity of substance use and psychiatric comorbidity, would be suggestive of a possible specific phenotype. The limitations and implications of the study are discussed.