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.     

Cannabis,psychosis and schizophrenia: unravelling a complex interaction

The relationship between cannabis and psychosis and schizophrenia has tested the field of addiction for decades, and in some ways serves as measure of our ability to provide a credible contribution to public health. As cannabis is used widely, many people are interested in the risks the drug poses to mental health. This paper focuses upon a seminal study examining this, the trajectory of subsequent research findings and what this has meant for understanding and communicating risk factor information. These studies provided evidence of a dose–response relationship between cannabis and psychosis, and that for those individuals with schizophrenia cannabis exacerbated their symptoms. The findings fit with a multi‐causal model in which vulnerability interacts with a precipitating agent to produce a disease outcome. Even though this is a common model in epidemiology, it has proved difficult to communicate it in this case. This may be because at a population level the increased risk is weak and the vulnerabilities relatively rare. It may also be because people bring strongly held preconceptions to interpreting a complex multi‐causal phenomenon.     

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.     

Major depression in patients with substance use disorders: relationship to 12-Step self-help involvement and substance use outcomes

Aims Many patients treated for substance use disorders (SUDs) who become involved in 12‐Step self‐help groups have improved treatment outcomes. However, due to high rates of psychiatric comorbidity and major depressive disorder (MDD), among SUD patients in particular, concerns have been raised over whether these benefits extend to dual diagnosis patients. This study examined the influence of comorbid MDD among patients with SUDs on 12‐Step self‐help group involvement and its relation to treatment outcome. Design A quasi‐experimental, prospective, intact group design was used with assessments completed during treatment, and 1 and 2 years postdischarge. Participants A total of 2161 male patients recruited during in‐patient SUD treatment, of whom 110 had a comorbid MDD diagnosis (SUD‐MDD) and 2051 were without psychiatric comorbidity (SUD‐only). Findings SUD‐MDD patients were initially less socially involved in and derived progressively less benefit from 12‐Step groups over time compared to the SUD‐only group. However, substance use outcomes did not differ by diagnostic cohort. In contrast, despite using substantially more professional out‐patient services, the SUD‐MDD cohort continued to suffer significant levels of depression. Conclusions Treatment providers should allocate more resources to targeting depressive symptoms in SUD‐MDD patients. Furthermore, SUD‐MDD patients may not assimilate as readily into, nor benefit as much from, traditional 12‐Step self‐help groups such as Alcoholics Anonymous, as psychiatrically non‐comorbid patients. Newer, dual‐diagnosis‐specific, self‐help groups may be a better fit for these patients, but await further study.     

Teenage drinking and the onset of alcohol dependence: a cohort study over seven years

AIM: To determine whether adolescent alcohol use and/or other adolescent health risk behaviour predisposes to alcohol dependence in young adulthood. DESIGN: Seven-wave cohort study over 6 years. PARTICIPANT: A community sample of almost two thousand individuals followed from ages 14-15 to 20-21 years. OUTCOME MEASURE: Diagnostic and Statistical Manual volume IV (DSM-IV) alcohol dependence in participants aged 20-21 years and drinking three or more times a week. FINDINGS: Approximately 90% of participants consumed alcohol by age 20 years, 4.7% fulfilling DSM-IV alcohol dependence criteria. Alcohol dependence in young adults was preceded by higher persisting teenage rates of frequent drinking [odds ratio (OR) 8.1, 95% confidence interval (CI) 4.2, 16], binge drinking (OR 6.7, 95% CI 3.6, 12), alcohol-related injuries (OR 4.5 95% CI 1.9, 11), intense drinking (OR 4.8, 95% CI 2.6, 8.7), high dose tobacco use (OR 5.5, 95% CI 2.3, 13) and antisocial behaviour (OR 5.9, 95% CI 3.3, 11). After adjustment for other teenage predictors frequent drinking (OR 3.1, 95% CI 1.2, 7.7) and antisocial behaviour (OR 2.4, 95% CI 1.2, 5.1) held persisting independent associations with later alcohol dependence. There were no prospective associations found with emotional disturbance in adolescence. CONCLUSION: Teenage drinking patterns and other health risk behaviours in adolescence predicted alcohol dependence in adulthood. Prevention and early intervention initiatives to reduce longer-term alcohol-related harm therefore need to address the factors, including alcohol supply, that influence teenage consumption and in particular high-risk drinking patterns.     

Gender differences in the association between substance use and elevated depressive symptoms in a general adolescent population

AIMS: This study explores gender differences in the association between substance use and elevated depressive symptoms in the general adolescent population. DESIGN: Cross-sectional self-reported anonymous survey, the 2002/2003 Student Drug Use Survey in the Atlantic Provinces. The sample design was a single-stage cluster sample of randomly selected classes stratified by grade and region. SETTING: The four Atlantic provinces of Canada. PARTICIPANTS: A total of 12 771 students in junior and senior high schools of the public school systems, representing a response rate of about 97%. The average age of participants was 15.2 years. MEASUREMENTS: The measure of elevated depressive symptoms was a 12-item version of the CES-D with three categories of depression risk validated in a companion study. FINDINGS: The prevalence of very elevated depressive symptoms was 8.6% in females and 2.6% in males. Alcohol use and cigarette smoking were found to be independent predictors of elevated depressive symptoms in females, but not males; cannabis use was found to be an independent predictor of elevated depressive symptoms in both males and females. Age was found to have a curvilinear relationship with elevated depressive symptoms in females but not in males. The adolescent's academic performance and province of residence were found to be independent risk factors of elevated depressive symptoms among both males and females. About 10.3% of adolescents considered to be potential candidates for needing help reported having received help because they felt depressed. CONCLUSIONS: The association between depression risk and age, alcohol use, cigarette smoking and cannabis use in the general adolescent population is not straightforward and may differ according to gender. There is unmet need for help for depression among adolescents.     

Co-occurrence of obsessive-compulsive disorder and substance use disorder in the general population

Aim Very little is known about the relationship between obsessive–compulsive disorder (OCD) and substance use disorder (SUD). The aim of this study is to compare the co‐occurrence of OCD with SUD to the co‐occurrence of SUD with other psychiatric disorders in a representative community sample. Design In order to examine the association of SUD and OCD, logistic regression analyses were used generating odds ratios and 95% confidence intervals for life‐time prevalence and 12‐month prevalence. Setting and participants Cross‐sectional data were derived from the Netherlands Mental Health Survey and Incidence Study (NEMESIS), a large representative sample of the Dutch population (n = 7076). Measurements The Composite International Diagnostic Interview (CIDI) 1.1 was used to assess Diagnostic and Statistical Manual of Mental Disorders Axis I criteria for psychiatric disorders. Findings The life‐time and 12‐month odds of being diagnosed with SUD in subjects with OCD are significantly higher than the odds of SUD for people without a psychiatric disorder. In men, the co‐occurrence of substance dependence and OCD is significantly higher than the co‐occurrence of substance dependence and other psychiatric disorders, whereas in women this co‐occurrence does not differ significantly. Conclusions The co‐occurrence of substance dependence in obsessive–compulsive disorder is higher than the co‐occurrence of substance dependence in other non‐obsessive–compulsive disorder DSM disorders, especially in men.     

Contingency management for treatment of substance use disorders: a meta-analysis

AIMS: To examine the effectiveness of contingency management (CM) techniques in treating substance use disorders (i.e. illicit drugs, alcohol, tobacco). DESIGN: Meta-analysis was used to determine the average effect size and potential moderators in 47 comparisons of the effectiveness of CM from studies based on a treatment-control group design and published between 1970 and 2002. FINDINGS: The mean effect size (ES) of CM was positive, with a magnitude of d = 0.42 using a fixed effects model. The magnitude of the ES declined over time, following treatment. CM was more effective in treating opiate use (d = 0.65) and cocaine use (d = 0.66), compared with tobacco (d = 0.31) or multiple drugs (d = 0.42). Larger effect sizes were associated with higher researcher involvement, earlier studies and shorter treatment duration. CONCLUSIONS: Study findings suggest that CM is among the more effective approaches to promoting abstinence during the treatment of substance use disorders. CM improves the ability of clients to remain abstinent, thereby allowing them to take fuller advantage of other clinical treatment components.     

Cardiovascular monitoring of a city over 30 years

This lecture on population studies was given in memory and honourof the late Professor Frederick Epstein. It relates to studiesperformed in Göteborg, Sweden. The main topics discussedin the presentation are: Coronary heart disease and stroke incidence according to theMONICA Project. Risk factors with special emphasis on relative and populationattributable risk. Incidence and mortality of coronary heart disease in hospitaland out of hospital. Quantitative aspects on treatment and prevention of myocardialinfarction. The analysis was based upon a Myocardial Infarction Registerwhich started in 1970, cross-sectional and prospective populationstudies primarily among men which started in 1963, cross-sectionalstudies among men and women based upon population studies (theMONICA Project) as well as studies of myocardial infarction.We have also been involved in many intervention trials in primaryand secondary prevention regarding physical training, beta-blockers,thrombolytics, aspirin, anti-arrhythmics, ACE-inhibitors andlipid lowering drugs. In the Primary Prevention Study it was found during a 16 years'follow-up that the coronary heart disease risk was related toentry level of serum cholesterol both among those who had signsof coronary heart disease or angina pectoris, as well as amongthose with no such previous coronary heart disease events atentry. For each cholesterol level, the risk was about seventimes higher among those who had had a myocardial infarctioncompared to those without any coronary heart disease event atentry. In those with angina the risk was about three to fourtimes higher. An example shows how important it is to take theso-called ‘regression dilution bias’ into account,which results in steeper risk factor-incidence curves. The concept of ‘population attributable risk’ isalso discussed. It is a general finding that the many with moderateelevations of risk factors contribute to most disease events.This is true for smoking, serum cholesterol, blood pressureetc. Results from various prospective studies have repeatedlydemonstrated three main risk factors for coronary heart disease:cholesterol, high blood pressure and smoking, and they explainmore than 90% of infarct cases in the middle-aged population.Other risk factors, including psychological, are, however, alsoof some importance and they are discussed briefly. The Göteborg population studies started in 1963. The datato 1990 show that among men there has been a decline in serumcholesterol and blood pressure, which has resulted in a declinein risk for coronary heart disease of 37%, well compatible withthe registered decline of 30–40% in coronary heart diseaseincidence among men aged 45–54 years. Simultaneously,there has been a marked decline, especially among men, of 28-dayfatality among hospitalized patients, but because most deathsoccur outside hospital the decline in incidence has had greaterimportance for overall coronary heart disease mortality. Several studies have demonstrated the importance of stoppingsmoking, at least after myocardial infarction. Other interventionsafter a myocardial infarction are also important for the outcome,which has improved considerably over the last 20 years. In thegeneral population in whom there is no sign of coronary heartdisease, it is important to reduce risk factors among the manywith moderate risk, by stopping smoking and changing diet.