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Abstract: Background: Despite clinical optimization of methadone doses, as many as 53% of patients experience significant and unacceptable levels inter-dose opioid withdrawal some of the time. Little is known about the relationship between perceived inter-dose opioid withdrawal and patient characteristics in methadone maintenance treatment. Methods: Ninety stabilized MMT patients were recruited and divided into three satisfaction groups (holders (H), partial holders (PH), and nonholders (NH)) based on their perceived opioid withdrawal as assessed by a guided self-report process. A battery of subjective assessments was administered during the approximate trough methadone condition. The primary measures were the Subjective Opioid Withdrawal Scale (SubOWS), Hopkins Symptom Checklist-90 (SCL-90), Obsessive–Compulsive Drug Use Survey (OCDUS), Profile of Mood States (POMS), and Neo Personality Inventory (NEO). Results: Nonholders experienced more opioid withdrawal (SubOWS—NH: 22.0±8.8 vs. PH: 12.2±8.2 vs. H: 9.3±10.0, p <0.001) and craving (OCDUS—NH: 11.4±8.8 vs. PH: 6.4±6.9 vs. H: 6.5±6.2, p =0.016). Holders experienced less Obsessive/Compulsive psychological distress (SCL-90—NH: 15.3±8.1 vs. PH: 12.3±7.3 vs. H: 6.6±5.1, p <0.001), Depression/Dejection (POMS—NH: 19.7±13.7 vs. PH: 17.2±13.2 vs. H: 7.9±10.4, p =0.002), and neurotic personality (NEO—NH: 63.3±12.3 vs. PH: 60.9±10.0 vs. H: 54.0±8.8, p =0.006). Partial holders had a less agreeable personality (NEO—NH: 44.2±8.6 vs. PH: 38.0±10.6 vs. H: 47.6±11.7, p =0.002). Conclusions: Physical opioid withdrawal is an important factor in understanding patient satisfaction with MMT. However, patient characteristics, such as level of psychological distress and negative mood, may also need to be considered because of their relationship with perceived inter-dose opioid withdrawal symptoms and patient satisfaction. [Copyright &y& Elsevier]

To characterize prescription opioid dependent patients in a methadone maintenance treatment (MMT) program, a detailed retrospective chart review of new admissions (1997–1999, n=178, mean age=34.5±0.7 years, 65% male) was conducted. At admission most patients (83%) had been using prescription opioids (±heroin). Four groups were identified: 24% had used prescription opioids only; 24% used prescription opioids initially and heroin later; 35% used heroin first and prescription opioids subsequently; and 17% had used heroin only (this group was significantly younger: mean age 26±1 years, P=0.0001). Subjects reported regular use of prescription opioids at higher than therapeutic dosages. For example, in the ‘prescription opioid only’ group the reported mean (±S.E.) number of codeine or oxycodone-containing tablets consumed daily was 23 (±6) tablets and 21 (±3) tablets, respectively. There were no significant differences found amongst the groups in measures of social stability. Those dependent on prescription opioids alone were less likely to use illicit non-opioid drugs or to be associated with injection drug use. Those that used prescription opioids only or initially were more likely to have ongoing pain problems and to be involved in psychiatric treatment. Further research is required to better elucidate the complex relationships between pain, mental health and addiction in order to develop optimal prevention and treatment strategies for prescription opioid dependence. [Copyright &y& Elsevier]

Over the past several years there have been repeated calls for expansion of availability of methadone maintenance in several jurisdictions. Important stakeholders in the expansion of methadone maintenance treatment (MMT) are existing treatment providers. This study describes the impact of the rapid expansion in treatment availability in Ontario on the long-standing MMT program of the Centre for Addiction and Mental Health (CAMH). This expansion occurred through enlarging existing treatment programs, the provision of MMT in private physicians’ offices and the establishment of new clinics. With expansion in the community, demand for the clinic-based treatment of the CAMH MMT program did not drop, in fact the patient population was able to continue to grow. There was a broadening of the patient profile in the program including patients who were better educated, more likely to be employed and less likely to be currently injecting (although with a significant history of past injection drug use). Moreover, in the face of these changes, excellent treatment retention was maintained. This suggests that the expansion in treatment availability did not impact negatively on the existing program but rather enabled access for a group of higher functioning opioid dependent patients who were previously being deterred from treatment entry by the large waiting lists and the need for priority access for pregnant and HIV positive heroin users. These findings should provide encouragement for MMT providers in jurisdictions anticipating or undergoing expansion of treatment availability. [Copyright &y& Elsevier]

Background: Although driving under the influence of cannabis is increasingly common among young adults, little is known about residual effects on driver behavior. This study examined acute and residual effects of smoked cannabis on simulated driving performance of young cannabis users.Methods: In this double-blind, placebo-controlled, parallel-group randomized clinical trial, cannabis users (1-4 days/week) aged 19-25 years were randomized with a 2:1 allocation ratio to receive active (12.5% THC) or placebo (0.009% THC) cannabis in a single 750 mg cigarette. A median split (based on whole-blood THC concentrations at the time of driving) was used to divide the active group into low and high THC groups. Our primary outcome was simulated driving performance, assessed 30 min and 24 and 48 h after smoking. Secondary outcomes included blood THC concentrations, subjective drug effects, and heart rate.Results: Ninety-six participants were randomized, and 91 were included in the final analysis (30 high THC, 31 low THC, 30 placebo). Mean speed (but not lateral control) significantly differed between groups 30 min after smoking cannabis (p ≤ 0.02); low and high THC groups decreased their speed compared to placebo. Heart rate, VAS drug effect and drug high increased significantly immediately after smoking cannabis and declined steadily after that. There was little evidence of residual effects in any of the measures.Conclusion: Acutely, cannabis caused decreased speed, increased heart rate, and increases in VAS drug effect and drug high. There was no evidence of residual effects on these measures over the two days following cannabis administration. [ABSTRACT FROM AUTHOR]

Background: Opioids have high abuse potential and pose a major public health concern. Yet, a large percentage of individuals exposed to opioids do not develop problematic use. Individual differences in opioid abuse potential are not well understood.Methods: This within-subject (N = 16), double-blind, double-dummy, human laboratory study evaluated individual differences in response to dose (placebo, low, medium, high) following administration of heroin and hydromorphone through intravenous and subcutaneous routes, in opioid-experienced but non physically-dependent participants. Outcomes were self-reported visual analog scale (VAS) ratings (High, Liking, Drug Effect, Good Effect, Rush), pupil diameter change from baseline, and crossover point on the Drug vs. Money questionnaire. The degree to which results were consistent across measures within an individual was assessed using a mixed-effects model from which an intraclass correlation coefficient measure of between and within-subject variance was derived.Results: The mixed effects model fit was significant (p < 0.0001) and revealed that 85.5% of the explainable variance was due to between-subject effects, suggesting the responses within an individual were highly consistent. Visual inspection reveals a myriad response pattern across participants, with some demonstrating classic dose-effect responses and others not differentiating any active doses from placebo.Conclusions: Data suggest the abuse potential of opioids is significantly different between individuals but that the experience within an individual is highly consistent. Research to prospectively characterize and evaluate mechanisms underlying these differences is warranted and may provide a foundation to help identify persons at heightened risk of transitioning from opioid exposure to misuse and/or opioid use disorder. [ABSTRACT FROM AUTHOR]

Abstract: Background: Cocaine is one of the more commonly found illicit drugs in injured drivers. In this work, we examine the association between self-reported past year cocaine use and past year collision involvement in a large representative sample of adult drivers in Ontario. Methods: Data are based on the CAMH Monitor, an ongoing cross-sectional telephone survey of Ontario adults aged 18 and older. Five years of data (2002, 2003, 2004, 2006, 2008) were merged for this study (N =8107) due to survey item availability. Logistic regression analysis was performed to identify the risk of self-reported collision involvement within the past 12 months associated with past year use of cocaine, while controlling for sociodemographic, driving exposure and drinking–driving (as a function of drinking status) factors. Due to listwise deletion, the logistic regression model was based on a reduced sample (N =7284). Results: The prevalence of self-reported collision involvement within the past year was 18.9% among those who used cocaine in the past year compared to 7.4% of non-users. Logistic regression analysis, controlling for the potential confounding effects of age, gender, income, driving exposure and drinking–driving measures, found the odds of collision involvement in the preceding year among cocaine users was over twice that of non-users (OR=2.11, 95% CI=1.06–4.18). Conclusions: This study suggests that cocaine users are significantly more likely to report collision involvement in the past year. Additional work to confirm these observations, and to assess possible causal pathways, is needed. [Copyright &y& Elsevier]