Does smoking cannabis affect work commitment?

Aims This study aimed to examine the associations between cannabis use and work commitment Design We used a 25‐year panel survey initiated in 1985 with follow‐ups in 1987, 1989, 1993, 2003 and 2010. Registered data from a range of public registers were matched with individual responses for the entire period. Setting The panel survey was a nation‐wide study set in Norway. Participants A total of 1997 respondents born between 1965 and 1968 were included in the panel. Measurements Work involvement scale (WIS) was used to assess work commitment. Involvement with cannabis was based on self‐reported smoking of cannabis within the last 12 months and exposure to cannabis through friends. This information was categorized into ‘abstaining’, ‘exposed’, ‘experimented’ and ‘involved’. Control measures included socio‐economic background, mental health (HSCL‐10), education, work satisfaction, unemployment, receipt of social assistance, consumption of alcohol, alcohol‐related problems and use of other illicit drugs. Findings The level of work commitment was associated with involvement with cannabis. In 1993, when the respondents were in their mid‐20s, those who were involved or had experimented with cannabis displayed lower levels of work commitment than those who were abstaining or merely exposed to cannabis through friends (P < 0.05). Work commitment among those who experimented with cannabis converged towards the levels reported by abstainers and the exposed as they grew older, whereas those involved reported decreasing work commitment into adulthood (P < 0.001). Using linear regression models for panel data, an association with continued use of cannabis across the life‐course and a lowering of work commitment was established. Results remained significant even when controlling for a range of other factors known to be related to work commitment, such as socio‐economic background, education, labour market experiences, mental health and family characteristics (P < 0.05). Conclusions In Norway the use of cannabis is associated with a reduction in work commitment among adults.     

Cannabis and crime: findings from a longitudinal study

Aim   To examine the association between cannabis use during adolescence and young adulthood, and subsequent criminal charges.
Methods   Data were obtained from the Young in Norway Longitudinal Study. A population-based sample ( n  = 1353) was followed from 13 to 27 years of age. Data were gathered on cannabis use, alcohol consumption and alcohol problems, and use of other illegal substances such as amphetamines, cocaine and opiates. In addition, extensive information on socio-demographic, family and personal factors was collected. This data set was linked to individual-level information from official Norwegian crime statistics.
Findings   We found robust associations between cannabis use and later registered criminal charges, both in adolescence and in young adulthood. These associations were adjusted for a range of confounding factors, such as family socio-economic background, parental support and monitoring, educational achievement and career, previous criminal charges, conduct problems and history of cohabitation and marriage. In separate models, we controlled for alcohol measures and for use of other illegal substances. After adjustment, we still found strong associations between cannabis use and later criminal charges. However, when eliminating all types of drug-specific charges from our models, we no longer observed any significant association with cannabis use.
Conclusions   The study suggests that cannabis use in adolescence and early adulthood may be associated with subsequent involvement in criminal activity. However, the bulk of this involvement seems to be related to various types of drug-specific crime. Thus, the association seems to rest on the fact that use, possession and distribution of drugs such as cannabis is illegal. The study strengthens concerns about the laws relating to the use, possession and distribution of cannabis.     

Cannabis use and later life outcomes

AIM: To examine the associations between the extent of cannabis use during adolescence and young adulthood and later education, economic, employment, relationship satisfaction and life satisfaction outcomes. DESIGN: A longitudinal study of a New Zealand birth cohort studied to age 25 years. MEASUREMENTS: Measures of: cannabis use at ages 14-25; university degree attainment to age 25; income at age 25; welfare dependence during the period 21-25 years; unemployment 21-25 years; relationship quality; life satisfaction. Also, measures of childhood socio-economic disadvantage, family adversity, childhood and early adolescent behavioural adjustment and cognitive ability and adolescent and young adult mental health and substance use. FINDINGS: There were statistically significant bivariate associations between increasing levels of cannabis use at ages 14-21 and: lower levels of degree attainment by age 25 (P < 0.0001); lower income at age 25 (P < 0.01); higher levels of welfare dependence (P < 0.0001); higher unemployment (P < 0.0001); lower levels of relationship satisfaction (P < 0.001); and lower levels of life satisfaction (P < 0.0001). These associations were adjusted for a range of potentially confounding factors including: family socio-economic background; family functioning; exposure to child abuse; childhood and adolescent adjustment; early adolescent academic achievement; and comorbid mental disorders and substance use. After adjustment, the associations between increasing cannabis use and all outcome measures remained statistically significant (P < 0.05). CONCLUSIONS: The results of the present study suggest that increasing cannabis use in late adolescence and early adulthood is associated with a range of adverse outcomes in later life. High levels of cannabis use are related to poorer educational outcomes, lower income, greater welfare dependence and unemployment and lower relationship and life satisfaction. The findings add to a growing body of knowledge regarding the adverse consequences of heavy cannabis use.     

Cannabis use and subclinical positive psychotic experiences in early adolescence: findings from a Dutch survey

Aims To investigate the association between early cannabis use and subclinical psychotic experiences, distinguishing between five levels of use: never used, discontinued use (life‐time users who did not use in the preceding year), experimental use, regular use and heavy use. Design Cross‐sectional observational study. Setting Dutch Health Behaviour in School‐aged Children (HBSC) study, 2005 wave. Participants A total of 4552 secondary school children aged 12–16 years. Measurements Cannabis use, Community Assessment of Psychic Experiences (CAPE) positive scale, confounding factors: age, gender, family affluence, household composition, social support, alcohol use, cigarette smoking, ethnicity and urbanicity. Findings The association between cannabis use and subclinical positive symptoms was confirmed, and remained significant after extensive adjustment for potential confounders. Associations were found for all user groups, with strongest associations for the discontinued use group (β = 0.061, P = 0.000) and for the heavy use group (β = 0.065, P = 0.000). Conclusions There is an enduring association between cannabis use at an early age and subclinical positive psychotic experiences, even after abstaining from cannabis for at least 1 year.     

Childbirth, abortion and subsequent substance use in young women: a population-based longitudinal study

AIMS: To investigate the possible linkages between deliveries, abortions and subsequent nicotine dependence, alcohol problems and use of cannabis and other illegal drugs from the ages of 15-27 years. METHODS: Data were gathered as part of the Young in Norway Longitudinal Study, an 11-year follow-up of a representative sample of Norwegian adolescents and young adults. DESIGN, SETTING AND PARTICIPANTS: Information was obtained on (i) the history of childbirths and induced abortions for the participants between the ages of 15-27 years; (ii) measures of nicotine dependence, alcohol problems and use of cannabis and other illegal drugs; and (iii) socio-demographic, family and individual confounding factors. RESULTS: Those who had had an abortion had elevated rates of substance use and problems. Those who gave birth to a child had reduced rates of alcohol problems and cannabis use. These associations persisted after control for confounders. However, those women who still lived with the father of the aborted fetus were not at increased risk. CONCLUSIONS: Abortion in women may, under some circumstances, be associated with increased risk of nicotine dependence, alcohol problems and use of cannabis and other illegal drugs. The birth of a child may reduce the use of some substances.     

A flicker paradigm for inducing change blindness reveals alcohol and cannabis information processing biases in social users

Aim To apply a new paradigm using transient changes to visual scenes to explore information processing biases relating to ‘social’ levels of alcohol and cannabis use. Participants Male and female student volunteers (n = 200) not self‐reporting substance‐related problems. Setting Quiet testing areas throughout the university campus. Design A flicker paradigm, for inducing change blindness with lighter and heavier social users of alcohol (experiment 1, n= 100) and social users and non‐users of cannabis (experiment 2, n= 100), explored the associations between habitual level of use and the latency to detection of a single substance‐related or neutral change made to a scene of grouped substance‐related and neutral objects. Measurements Alcohol use was measured as the number of units of the heaviest drinking day from the previous week; cannabis use as the number of months of use in previous 12. Change–detection latency comparisons were used to evaluate processing biases. Findings In both experiments, (i) heavier social users detected substance‐related changes quicker than lighter and non‐users; (ii) lighter and non‐users detected substance‐neutral changes quicker than heavier users; (iii) heavier social users detected substance‐related quicker than substance‐neutral changes; and (iv) lighter and non‐users detected substance‐neutral changes quicker than substance‐related changes. Conclusions Alcohol and cannabis processing biases are found at levels of social use, have the potential to influence future consumption and for this reason merit further research.     

The efficacy of single-session motivational interviewing in reducing drug consumption and perceptions of drug-related risk and harm among young people: results from a multi-site cluster randomized trial

Aim To test whether a single session of motivational interviewing (discussing alcohol, tobacco and illicit drug use) would lead successfully to reduction in use of these drugs or in perceptions of drug‐related risk and harm among young people. Design Cluster randomized trial, allocating 200 young people in the natural groups in which they were recruited to either motivational interviewing (n = 105) or non‐intervention education‐as‐usual control condition (n = 95). Setting Ten further education colleges across inner London. Participants Two hundred young people (age range 16–20 years) currently using illegal drugs, with whom contact was established through peers trained for the project. Intervention The intervention was adapted from the literature on motivational interviewing in the form of a 1‐hour single‐session face‐to‐face interview structured by a series of topics. Measurements Changes in self‐reported cigarette, alcohol, cannabis and other drug use and in a range of drug‐specific perceptions and other indicators of risk and harm. Measurement at recruitment and follow‐up interview 3 months later. Findings A good follow‐up rate (89.5%; 179 of 200) was achieved. In comparison to the control group, those randomized to motivational interviewing reduced their of use of cigarettes, alcohol and cannabis, mainly through moderation of ongoing drug use rather than cessation. Effect sizes were 0.37 (0.15–0.6), 0.34 (0.09–0.59) and 0.75 (0.45–1.0) for reductions in the use of cigarettes, alcohol and cannabis, respectively. For both alcohol and cannabis, the effect was greater among heavier users of these drugs and among heavier cigarette smokers. The reduced cannabis use effect was also greater among youth usually considered vulnerable or high‐risk according to other criteria. Change was also evident in various indicators of risk and harm, but not as widely as the changes in drug consumption. Conclusions This study provides the first substantial evidence of non‐treatment benefit to be derived among young people involved in illegal drug use in receipt of motivational interviewing. The targeting of multiple drug use in a generic fashion among young people has also been supported.     

Hypothalamic-pituitary-adrenal axis reactivity to social stress and adolescent cannabis use: the TRAILS study

Aims To investigate the relationship of life‐time and repeated cannabis use with hypothalamic–pituitary–adrenal (HPA) axis reactivity to social stress in a general population sample of adolescents. Design Adolescents who reported life‐time or repeated cannabis use, life‐time or repeated tobacco use and never use of either cannabis or tobacco were compared with respect to their HPA axis reactivity during the Groningen Social Stress Task (GSST), which was based on the Trier Social Stress Task. Setting A large prospective population study of Dutch adolescents [the TRacking Adolescents' Individual Lives Survey (TRAILS) study]. Participants A total of 591 adolescents (51% male) who participated in the GSST, which was an additional measurement during the third assessment wave. Measurements HPA axis stress‐reactivity was indexed by four cortisol samples collected before, during and after the GSST. Furthermore, all adolescents in our study completed self‐reported questionnaires on life‐time and repeated cannabis and tobacco use. Models were adjusted for sex, recent alcohol use, experimental session risk status, socio‐economic status, mood and time of the experimental session. Findings Life‐time cannabis users had significantly lower stress‐reactivity levels when compared to abstainers [odds ratio (OR) = 0.68, confidence interval (CI) = 0.55–0.85, P < 0.01] and life‐time tobacco users (OR = 0.79, CI = 0.64–0.98, P < 0.05). In addition, repeated cannabis users also exhibited lower stress‐reactivity levels when compared to life‐time ever users of either tobacco or cannabis (OR = 0.74, CI = 0.53–0.98, P < 0.05). Conclusions Lower hypothalamic–pituitary–adrenal‐axis stress‐reactivity in adolescents is related specifically to life‐time and repeated cannabis use.     

Working hours and alcohol problems in early adulthood

Aims To examine the associations between working hours and alcohol‐related problems during early adulthood. Design and setting Longitudinal study of a birth cohort born in Christchurch, New Zealand in 1977 and studied to age 30. Participants A total of 1019 participants with data available for working hours and alcohol‐related problems at either age 25 or 30. Measurements Weekly working hours in paid employment; frequent alcohol use; diagnosis of alcohol abuse/dependence; number of symptoms of alcohol abuse/dependence. Associations between working hours and alcohol‐related problems were adjusted for covariates including measures of: parental and family background; personality and behaviour; IQ and educational achievement; recent negative life events; recent mental health problems; and current partner and family circumstances. Findings Longer work hours were associated significantly with more frequent alcohol use (P < 0.0001), higher rates of alcohol abuse/dependence (P = 0.0001) and a greater number of alcohol abuse/dependence symptoms (P = 0.01). These associations were adjusted for a wide range of confounding factors. After adjustment there remained significant (P < 0.05) associations between working hours and alcohol‐related problems, with those working 50 or more hours per week having rates of alcohol‐related problems 1.8–3.3 times higher than those who were not working. The associations between work hours and alcohol use were similar for males and females. Conclusions Longer work hours appear to be associated with higher rates of alcohol‐related problems, including more frequent alcohol use, higher rates of alcohol abuse/dependence and a greater number of alcohol abuse/dependence symptoms. These associations remain even after extensive adjustment for confounding.     

A randomized controlled trial of a brief intervention for illicit drugs linked to the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) in clients recruited from primary health-care settings in four countries

Aims This study evaluated the effectiveness of a brief intervention (BI) for illicit drugs (cannabis, cocaine, amphetamine‐type stimulants and opioids) linked to the World Health Organization (WHO) Alcohol, Smoking and Substance Involvement Screening Test (ASSIST). The ASSIST screens for problem or risky use of 10 psychoactive substances, producing a score for each substance that falls into either a low‐, moderate‐ or high‐risk category. Design Prospective, randomized controlled trial in which participants were either assigned to a 3‐month waiting‐list control condition or received brief motivational counselling lasting an average of 13.8 minutes for the drug receiving the highest ASSIST score. Setting Primary health‐care settings in four countries: Australia, Brazil, India and the United States. Participants A total of 731 males and females scoring within the moderate‐risk range of the ASSIST for cannabis, cocaine, amphetamine‐type stimulants or opioids. Measurements ASSIST‐specific substance involvement scores for cannabis, stimulants or opioids and ASSIST total illicit substance involvement score at baseline and 3 months post‐randomization. Findings Omnibus analyses indicated that those receiving the BI had significantly reduced scores for all measures, compared with control participants. Country‐specific analyses showed that, with the exception of the site in the United States, BI participants had significantly lower ASSIST total illicit substance involvement scores at follow‐up compared with the control participants. The sites in India and Brazil demonstrated a very strong brief intervention effect for cannabis scores (P < 0.005 for both sites), as did the sites in Australia (P < 0.005) and Brazil (P < 0.01) for stimulant scores and the Indian site for opioid scores (P < 0.01). Conclusions The Alcohol, Smoking and Substance Involvement Screening Test‐linked brief intervention aimed at reducing illicit substance use and related risks is effective, at least in the short term, and the effect generalizes across countries.     

Predictors of age at onset of tobacco and cannabis use in Danish adolescents

Introduction: Early onset of tobacco and cannabis use predicts later substance abuse and risk behaviour and has large health consequences. Objectives: The aim of this study was to examine risk factors for the age at onset of smoking and cannabis use among a group of Danish children between 7 years and 18 years of age. Methods: Four hundred and eighty randomly selected children and their parents participated in a study about the prevalence of asthma. The study included questions about alcohol, tobacco and cannabis use. The children were interviewed face‐to‐face while the parents answered a questionnaire. Results: The age at onset of daily smoking was significantly associated with the adolescents' tendency to binge drink [hazard ratio 4.78, 95% confidence interval (CI) (1.85–12.34), P = 0.001) and to use hard drugs [hazard ratio 2.81, 95% CI (1.03–7.78), P = 0.047], whereas the age at onset of cannabis use was significantly associated with binge drinking [hazard ratio 3.29, 95% CI (1.51–7.20), P = 0.003] and cigarette smoking [hazard ratio 2.51, 95% CI (1.26–5.00), P = 0.009]. There were no significant effect of the parents' smoking and alcohol habits, their socioeconomic or marital status on the adolescent' age at onset of smoking or cannabis. Conclusion: This study shows a close connection between adolescent tobacco and cannabis use and alcohol habits. Knowledge of this is important when planning future prevention strategies. Please cite this paper as: Wium‐Andersen IK, Wium‐Andersen MK, Becker U and Thomsen SF. Predictors of age at onset of tobacco and cannabis use in Danish adolescents. Clin Respir J 2010; 4: 162–167.     

Exploration of the Comorbidity of Cannabis Use Disorders and Mental Health Disorders among Inpatients Presenting to All Hospitals in New South Wales,Australia

Background: Cannabis is one of the most commonly used illegal psychoactive substances and its use often coexists with mental health disorders. Objectives: This study explores the relationships between cannabis use disorders and some common mental health disorders. Methods: Admissions to all New South Wales (NSW) hospitals were analyzed. The data were extracted from the NSW Department of Health Inpatient Statistics Data Collection for the period 1 July 2006 to 30 June 2007. Readmissions within 28 days were excluded. Data extraction and analyses were performed by using the SAS program. Chi-square tests and odds ratio were used to examine the association between cannabis use disorder and mental health disorders. Results: Of the 1.8 million admissions, associations between cannabis use disorders and mental health disorders were strong (odds ratio = 7.8–10.7, p < .001). Inpatients (53.8%) who used cannabis had at least one identifiable mental disorder. Higher comorbidity rates were observed for females (39.6%) and for those aged between 30 and 49 years. Cannabis use disorder comorbid with the most common mental disorders were: anxiety disorder (3.4%), bipolar affective disorder (5.7%), major depressive disorder (10.9%), personality disorder (9.2%), schizophrenia (15.0%), and severe stress disorder (8.7%). Cannabis use disorder has strong associations with these mental health disorders (odds ratio 4.8–34.8). The average length of stay (ALOS) for cannabis use disorders was 9.0 days and the ALOS for the most common mental health disorders was 11.0 days. Conclusions and implications: This study provides detailed information about the association between cannabis use disorders and mental health disorders and extends our understanding of comorbidity presentations in inpatient admissions.     

Linking substance use with symptoms of subclinical psychosis in a community cohort over 30 years

Aims The aim of the study was to examine the temporal associations between substance use and subclinical psychosis symptoms. Design Data from a prospective community study sampled within a single cohort over 30 years (1978–2008) were analysed with discrete‐time hazard models. Setting General population‐based sample. Participants At initial sampling in 1978 males (n = 292) were 19 and females (n = 299) were 20 years old. Measurements Two psychosis syndromes representing ‘schizotypal signs’ and ‘schizophrenia nuclear symptoms’ and various substance use variables including cannabis, alcohol, tobacco and multiple‐drug use (i.e. cannabis combined with other drugs). Findings In bivariate analyses, schizotypal signs were predominantly associated with regular cannabis use in adolescence (OR = 2.29, 95% CI 1.32–3.97). Schizophrenia nuclear symptoms were mainly related to alcohol (OR = 1.84, 95% CI 1.00–3.38) and multiple‐drug use (OR = 2.35, 95% CI 1.38–4.02) during adolescence. Multivariate analyses showed that, in particular, regular cannabis use during adolescence was associated with the occurrence of subsequent schizotypal symptoms over a 30‐year period (OR = 2.60, 95% CI; 1.59–4.23), whereas multiple‐drug use in adolescence was associated predominantly with schizophrenia nuclear symptoms (OR = 1.75, 95% CI 1.01–3.03). Alcohol misuse was only slightly associated with the onset of such symptoms. Conclusions A significant portion of the occurrence of subclinical psychosis symptoms in adulthood can be attributed to excessive cannabis and multiple‐drug use during adolescence. This is in line with the hypothesis that long‐term sensitization of dopaminergic brain receptors plays a role in developing psychotic symptoms.     

Changes in cannabis use and its consequences over 3 years in a remote indigenous population in northern Australia

Background Few studies describe cannabis use in indigenous populations, and no longitudinal studies are available in Australia. We conducted 3‐year follow‐up interviews and assessments in Aboriginal communities in Arnhem Land (Northern Territory, NT). Methods A randomly selected sample (n = 161; 80 males, 81 females aged 13–36 years) was assessed in October 2001 and then reassessed in September 2004. An opportunistically recruited sample (n = 104; 53 males, 51 females aged 13–36 years) was also interviewed in 2001 and followed‐up in 2004. Cannabis and other substance use were determined by combining proxy assessments by local Aboriginal health workers, medical records and data from interviews. Changes in cannabis use and symptoms of misuse were assessed using McNemar's test for paired proportions and the Wilcoxon signed rank test. Logistic regression assessed associations between clinical presentations and cannabis use at both time‐points. Results Those who used cannabis at both baseline and follow‐up were at greater risk than those who never used it to have suffered: auditory hallucinations; suicidal ideation; and imprisonment. In the randomly selected cohort there were fewer cannabis users at follow‐up than at baseline (P = 0.003). The reduction was evident in females generally (P = 0.008) and older males (aged = 16 at baseline) (P = 0.007). In those interviewed at both baseline and follow‐up we measured no statistically significant reduction in frequency and levels of use, although fewer cannabis users reported symptoms of misuse such as: fragmented thought processes; memory disruption; difficulties controlling use; and auditory and visual hallucinations. Conclusions Modest reductions in cannabis use and its consequences in this population were demonstrated. These may be the result of enhanced supply control and broader socio‐political changes.     

Overall survival in lower IPSS risk MDS by receipt of iron chelation therapy,adjusting for patient‐related factors and measuring from time of first red blood cell transfusion dependence: an MDS‐CAN analysis

Analyses suggest iron overload in red blood cell (RBC) transfusion‐dependent (TD) patients with myleodysplastic syndrome (MDS) portends inferior overall survival (OS) that is attenuated by iron chelation therapy (ICT) but may be biassed by unbalanced patient‐related factors. The Canadian MDS Registry prospectively measures frailty, comorbidity and disability. We analysed OS by receipt of ICT, adjusting for these patient‐related factors. TD International Prognostic Scoring System (IPSS) low and intermediate‐1 risk MDS, at RBC TD, were included. Predictive factors for OS were determined. A matched pair analysis considering age, revised IPSS, TD severity, time from MDS diagnosis to TD, and receipt of disease‐modifying agents was conducted. Of 239 patients, 83 received ICT; frailty, comorbidity and disability did not differ from non‐ICT patients. Median OS from TD was superior in ICT patients (5·2 vs. 2·1 years; P < 0·0001). By multivariate analysis, not receiving ICT independently predicted inferior OS, (hazard ratio for death 2·0, P = 0·03). In matched pair analysis, OS remained superior for ICT patients (P = 0·02). In this prospective, non‐randomized analysis, receiving ICT was associated with superior OS in lower IPSS risk MDS, adjusting for age, frailty, comorbidity, disability, revised IPSS, TD severity, time to TD and receiving disease‐modifying agents. This provides additional evidence that ICT may confer clinical benefit.     

Denise Kandel's classic work on the gateway sequence of drug acquisition

During the early 1970s Denise Kandel and her colleagues documented an ‘invariant sequence’ in initiation of drug use: starting with alcohol and tobacco, progressing to cannabis and then to other illicit, or ‘harder’ drugs. This observation, which became known as the ‘gateway sequence’ of drug use, has been influential in policy debates but remains highly contentious, with the area of greatest controversy focusing upon whether cannabis use increases risk causally for initiation of other illicit drugs. While numerous studies have replicated Kandel's initial findings (sequence of onset) and reported that associations between cannabis use and the use of other illicit drugs remain after controlling for potentially confounding factors, the mechanisms underlying these observed associations remain hotly debated. In particular, it is possible that the observed associations are non‐causal but reflect the influence of confounding factors which influence both early‐onset drug use and subsequent progressions. However, research employing a range of techniques to address this issue has been unable to discount the possibility that associations between earlier and subsequent drug use reflect causal processes. This paper reviews Kandel's ongoing contributions to this field, which span 45 years, and discusses both the influence of her work and the controversy that it has aroused.     

Evaluation of the possible influence of hepatitis C virus and liver fibrosis on HIV type 1 immunological and virological outcomes

Objectives The aim of the study was to evaluate the possible effect of hepatitis C virus (HCV) coinfection on the viroimmunological outcomes of HIV‐1 infection. Methods A cross‐sectional study of 805 patients with active HCV infection receiving or not receiving antiretroviral therapy (ART) was carried out. Results A number of parameters were significantly associated with undetectable HIV‐1 viral load in univariate analyses, such as age, toxic habits, CD4 cell count, liver test results, HCV viral load and ART. However, only current ART (P<0.0001), CD4 cell count (P<0.0001), age (P=0.004) and current injecting drug use (P=0.02) were independently associated with undetectable viral load in multivariate analysis. None of the many HCV‐ and liver fibrosis‐related parameters analysed showed a significant association with HIV‐1 viral load or CD4 cell count in multivariate analyses, with the exception of the annual fibrosis progression index which almost reached statistical significance in the subgroup of ART‐untreated patients (P=0.06) and was inversely predictive of CD4 cell count in the whole group (P=0.007). However, its relative weight was modest, as it only explained 0.8% of the total variability in CD4 cell count. Conclusions HCV‐related parameters did not significantly affect virological and immunological outcomes of HIV‐1 infection in ART‐treated and untreated patients. In contrast, liver fibrosis, as measured using the annual fibrosis progression index, was inversely associated with CD4 cell count, although its weight was relatively small. Therefore, HCV‐ and liver fibrosis‐related factors do not seem appreciably to influence these outcomes from a practical viewpoint in ART‐naïve patients, nor impair CD4 and HIV‐1 viral load responses to ART.     

Self-reported cannabis use characteristics,patterns and helpfulness among medical cannabis users

Objectives: Little research has investigated the demographic and symptom profile of medical cannabis users in states in the USA that have legalized cannabis use. Methods: In the present cross-sectional study, we investigated the demographic profile of 217 adults currently receiving medical cannabis, as well as differences in problematic use and perceived helpfulness in terms of (i) symptoms of psychological disorders and pain, and (ii) motives for use. Results: Findings indicated that medical cannabis users (i) use and perceive cannabis to be beneficial for multiple conditions, some for which cannabis is not specifically prescribed or allowed at the state level; and (ii) report similar rates of disordered use as compared with population estimates among regular users. Furthermore, problematic cannabis use was predicted by several symptoms of psychological disorders (e.g. depression) and a variety of use motives (e.g. coping), while cannabis was reported as particularly helpful among those with several psychological symptoms (e.g. traumatic intrusions), as well as those reporting use for social anxiety reasons. Conclusions: Results are discussed in terms of future directions for research given the current debates regarding legalization of cannabis for medical purposes and, more generally, the lack of empirical data to inform such debates.     

Combining cognitive behavioral therapy and contingency management to enhance their effects in treating cannabis dependence: less can be more, more or less

Aims To evaluate reciprocal enhancement (combining treatments to offset their relative weaknesses) as a strategy to improve cannabis treatment outcomes. Contingency management (CM) with reinforcement for homework completion and session attendance was used as a strategy to enhance cognitive–behavioral therapy (CBT) via greater exposure to skills training; CBT was used as a strategy to enhance durability of CM with rewards for abstinence. Setting Community‐based out‐patient treatment program in New Haven, Connecticut, USA. Design Twelve‐week randomized clinical trial of four treatment conditions: CM for abstinence alone or combined with CBT, CBT alone or combined with CM with rewards for CBT session attendance and homework completion. Participants A total of 127 treatment‐seeking young adults (84.3% male, 81.1% minority, 93.7% referred by criminal justice system, average age 25.7 years). Measurements Weekly urine specimens testing positive for cannabis, days of cannabis use via the time‐line follow‐back method. Findings Within treatment, reinforcing homework and attendance did not significantly improve CBT outcomes, and the addition of CBT worsened outcomes when added to CM for abstinence (75.5 versus 57.1% cannabis‐free urine specimens, F = 2.25, P = 0.02). The CM for abstinence condition had the lowest percentage of cannabis‐negative urine specimens and the highest mean number of consecutive cannabis‐free urine specimens (3.3, F = 2.33, P = 0.02). Attrition was higher in the CBT alone condition, but random effect regression analyses indicated this condition was associated with the greatest rate of change overall. Cannabis use during the 1‐year follow‐up increased most rapidly for the two enhanced groups. Conclusions Combining contingency management and cognitive–behavioural therapy does not appear to improve success rates of treatment for cannabis dependence in clients involved with the criminal justice system.