Characteristics of DSM-IV and ICD-10 cannabis dependence among Australian adults: results from the National Survey of Mental Health and Wellbeing

Prevalence of Cannabis Withdrawal Symptoms Among People With Regular or Dependent Use of Cannabinoids: A Systematic Review and Meta-analysis

IMPORTANCE

Cannabis withdrawal syndrome (CWS)-a diagnostic indicator of cannabis use disorder-commonly occurs on cessation of heavy and prolonged cannabis use. To date, the prevalence of CWS syndrome has not been well described, nor have the factors potentially associated with CWS.

OBJECTIVES

To estimate the prevalence of CWS among individuals with regular or dependent use of cannabinoids and identify factors associated with CWS.

DATA SOURCES

A search of literature from database inception to June 19, 2019, was performed using MEDLINE, Embase, PsycINFO, Web of Science, the Cumulative Index to Nursing and Allied Health Literature, ProQuest, Allied and Complementary Medicine, and Psychiatry online, supplemented by manual searches of reference lists of included articles.

STUDY SELECTION

Articles were included if they (1) were published in English, (2) reported on individuals with regular use of cannabinoids or cannabis use disorder as a primary study group, (3) reported on the prevalence of CWS or CWS symptoms using a validated instrument, (4) reported the prevalence of CWS, and (5) used an observational study design (eg, cohort or cross-sectional).

DATA EXTRACTION AND SYNTHESIS

All abstracts, full-text articles, and other sources were reviewed, with data extracted in duplicate. Cannabis withdrawal syndrome prevalence was estimated using a random-effects meta-analysis model, alongside stratification and meta-regression to characterize heterogeneity.

MAIN OUTCOMES AND MEASURES

Cannabis withdrawal syndrome prevalence was reported as a percentage with 95% CIs.

RESULTS

Of 3848 unique abstracts, 86 were selected for full-text review, and 47 studies, representing 23 518 participants, met all inclusion criteria. Of 23 518 participants included in the analysis, 16 839 were white (72%) and 14 387 were men (69%); median (SD) age was 29.9 (9.0) years. The overall pooled prevalence of CWS was 47% (6469 of 23 518) (95% CI, 41%-52%), with significant heterogeneity between estimates (I2 = 99.2%). When stratified by source, the prevalence of CWS was 17% (95% CI, 13%-21%) in population-based samples, 54% in outpatient samples (95% CI, 48%-59%), and 87% in inpatient samples (95% CI, 79%-94%), which were significantly different (P < .001). Concurrent cannabis (β = 0.005, P < .001), tobacco (β = 0.002, P = .02), and other substance use disorders (β = 0.003, P = .05) were associated with a higher CWS prevalence, as was daily cannabis use (β = 0.004, P < .001).

CONCLUSIONS AND RELEVANCE

These findings suggest that cannabis withdrawal syndrome appears to be prevalent among regular users of cannabis. Clinicians should be aware of the prevalence of CWS in order to counsel patients and support individuals who are reducing their use of cannabis.

Cannabis and Its Secondary Metabolites: Their Use as Therapeutic Drugs, Toxicological Aspects, and Analytical Determination

Although the medicinal properties of Cannabis species have been known for centuries, the interest on its main active secondary metabolites as therapeutic alternatives for several pathologies has grown in recent years. This potential use has been a revolution worldwide concerning public health, production, use and sale of cannabis, and has led inclusively to legislation changes in some countries. The scientific advances and concerns of the scientific community have allowed a better understanding of cannabis derivatives as pharmacological options in several conditions, such as appetite stimulation, pain treatment, skin pathologies, anticonvulsant therapy, neurodegenerative diseases, and infectious diseases. However, there is some controversy regarding the legal and ethical implications of their use and routes of administration, also concerning the adverse health consequences and deaths attributed to marijuana consumption, and these represent some of the complexities associated with the use of these compounds as therapeutic drugs. This review comprehends the main secondary metabolites of Cannabis, approaching their therapeutic potential and applications, as well as their potential risks, in order to differentiate the consumption as recreational drugs. There will be also a focus on the analytical methodologies for their analysis, in order to aid health professionals and toxicologists in cases where these compounds are present.

The cannabis withdrawal syndrome: current insights

The cannabis withdrawal syndrome (CWS) is a criterion of cannabis use disorders (CUDs) (Diagnostic and Statistical Manual of Mental Disorders - Fifth Edition) and cannabis dependence (International Classification of Diseases [ICD]-10). Several lines of evidence from animal and human studies indicate that cessation from long-term and regular cannabis use precipitates a specific withdrawal syndrome with mainly mood and behavioral symptoms of light to moderate intensity, which can usually be treated in an outpatient setting. Regular cannabis intake is related to a desensitization and downregulation of human brain cannabinoid 1 (CB1) receptors. This starts to reverse within the first 2 days of abstinence and the receptors return to normal functioning within 4 weeks of abstinence, which could constitute a neurobiological time frame for the duration of CWS, not taking into account cellular and synaptic long-term neuroplasticity elicited by long-term cannabis use before cessation, for example, being possibly responsible for cannabis craving. The CWS severity is dependent on the amount of cannabis used pre-cessation, gender, and heritable and several environmental factors. Therefore, naturalistic severity of CWS highly varies. Women reported a stronger CWS than men including physical symptoms, such as nausea and stomach pain. Comorbidity with mental or somatic disorders, severe CUD, and low social functioning may require an inpatient treatment (preferably qualified detox) and post-acute rehabilitation. There are promising results with gabapentin and delta-9-tetrahydrocannabinol analogs in the treatment of CWS. Mirtazapine can be beneficial to treat CWS insomnia. According to small studies, venlafaxine can worsen the CWS, whereas other antidepressants, atomoxetine, lithium, buspirone, and divalproex had no relevant effect. Certainly, further research is required with respect to the impact of the CWS treatment setting on long-term CUD prognosis and with respect to psychopharmacological or behavioral approaches, such as aerobic exercise therapy or psychoeducation, in the treatment of CWS. The up-to-date ICD-11 Beta Draft is recommended to be expanded by physical CWS symptoms, the specification of CWS intensity and duration as well as gender effects.

Mapping the manuals of madness: Comparing the ICD-10 and DSM-IV-TR using a network approach

The International Classification of Diseases and Related Health Problems (ICD) and the Diagnostic and Statistical Manual of Mental Disorders (DSM) represent dominant approaches to diagnosis of mental disorders. However, it is unclear how these alternative systems relate to each other when taking into account the symptoms that make up the disorders. This study uses a network approach to investigate the overlap in structure between diagnostic networks pertaining to ICD-10 and DSM-IV-TR. Networks are constructed by representing individual symptoms as nodes, and connecting nodes whenever the corresponding symptoms feature as diagnostic criteria for the same mental disorder. Results indicate that, relative to the DSM-IV-TR network, the ICD-10 network contains (a) more nodes, (b) lower level of clustering, and (c) a higher level of connectivity. Both networks show features of a small world, and have similar (of "the same") high centrality nodes. Comparison to empirical data indicates that the DSM-IV-TR network structure follows comorbidity rates more closely than the ICD-10 network structure. We conclude that, despite their apparent likeness, ICD-10 and DSM-IV-TR harbour important structural differences, and that both may be improved by matching diagnostic categories more closely to empirically determined network structures. Copyright © 2016 John Wiley & Sons, Ltd.

Marijuana dependence: not just smoke and mirrors

Marijuana (Cannabis sativa) is the most commonly used illicit drug worldwide as well as in the Unites States. Prolonged use of marijuana or repeated administration of its primary psychoactive constituent, Δ9-tetrahydrocannabinol (THC), can lead to physical dependence in humans and laboratory animals. The changes that occur with repeated cannabis use include alterations in behavioral, physiological, and biochemical responses. A variety of withdrawal responses occur in cannabis-dependent individuals: anger, aggression, irritability, anxiety and nervousness, decreased appetite or weight loss, restlessness, and sleep difficulties with strange dreams. But the long half-life and other pharmacokinetic properties of THC result in delayed expression of withdrawal symptoms, and because of the lack of contiguity between drug cessation and withdrawal responses the latter are not readily recognized as a clinically relevant syndrome. Over the past 30 years, a substantial body of clinical and laboratory animal research has emerged supporting the assertion that chronic exposure to cannabinoids produces physical dependence and may contribute to drug maintenance in cannabis-dependent individuals. However, no medications are approved to treat cannabis dependence and withdrawal. In this review, we describe preclinical and clinical research that supports the existence of a cannabinoid withdrawal syndrome. In addition, we review research evaluating potential pharmacotherapies (e.g., THC, a variety of antidepressant drugs, and lithium) to reduce cannabis withdrawal responses and examine how expanded knowledge about the regulatory mechanisms in the endocannabinoid system may lead to promising new therapeutic targets.

Psychometric modeling of abuse and dependence symptoms across six illicit substances indicates novel dimensions of misuse

AIMS

This study explored the factor structure of DSM III-R/IV symptoms for substance abuse and dependence across six illicit substance categories in a population-based sample of males.

METHOD

DSM III-R/IV drug abuse and dependence symptoms for cannabis, sedatives, stimulants, cocaine, opioids and hallucinogens from 4179 males born 1940-1970 from the population-based Virginia Adult Twin Study of Psychiatric and Substance Use Disorders were analyzed. Confirmatory factor analyses tested specific hypotheses regarding the latent structure of substance misuse for a comprehensive battery of 13 misuse symptoms measured across six illicit substance categories (78 items).

RESULTS

Among the models fit, the latent structure of substance misuse was best represented by a combination of substance-specific factors and misuse symptom-specific factors. We found no support for a general liability factor to illicit substance misuse.

CONCLUSIONS

Results indicate that liability to misuse illicit substances is drug class specific, with little evidence for a general liability factor. Additionally, unique dimensions capturing propensity toward specific misuse symptoms (e.g., tolerance, withdrawal) across substances were identified. While this finding requires independent replication, the possibility of symptom-specific misuse factors, present in multiple substances, raises the prospect of genetic, neurobiological and behavioral predispositions toward distinct, narrowly defined features of drug abuse and dependence.

Quantification of 11-nor-9-carboxy-δ9-tetrahydrocannabinol in human oral fluid by gas chromatography-tandem mass spectrometry

A sensitive and specific method for the quantification of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) in oral fluid collected with the Quantisal and Oral-Eze devices was developed and fully validated. Extracted analytes were derivatized with hexafluoroisopropanol and trifluoroacetic anhydride and quantified by gas chromatography-tandem mass spectrometry with negative chemical ionization. Standard curves, using linear least-squares regression with 1/x weighting were linear from 10 to 1000 ng/L with coefficients of determination >0.998 for both collection devices. Bias was 89.2%-112.6%, total imprecision 4.0%-5.1% coefficient of variation, and extraction efficiency >79.8% across the linear range for Quantisal-collected specimens. Bias was 84.6%-109.3%, total imprecision 3.6%-7.3% coefficient of variation, and extraction efficiency >92.6% for specimens collected with the Oral-Eze device at all 3 quality control concentrations (10, 120, and 750 ng/L). This effective high-throughput method reduces analysis time by 9 minutes per sample compared with our current 2-dimensional gas chromatography-mass spectrometry method and extends the capability of quantifying this important oral fluid analyte to gas chromatography-tandem mass spectrometry. This method was applied to the analysis of oral fluid specimens collected from individuals participating in controlled cannabis studies and will be effective for distinguishing passive environmental contamination from active cannabis smoking.

Agreement between DSM-IV and ICD-10 criteria for opioid use disorders in two Iranian samples

The aim of this study was to determine the agreement between the two systems in opioid users in the general population and a clinical sample. Two series of data were used in this study. The first was the data of 236 home-residing opioid abusers aged 15-64, who had previously participated in the Iran Mental Health Survey (IranMHS) in 2011, and the second was the data of 104 general psychiatry patients from inpatient or outpatient wards of two psychiatry hospitals in Tehran. Opioid use disorders were evaluated with CIDI-version 2.1. The disorders were assessed in all participants who used opioid substances for at least 5 times during the past 12months. In the sample from the general population, the agreement between the two systems on the diagnosis of dependence was excellent (0.81). The agreement between the two systems on the diagnosis of abuse and harmful use was 0.41. In the clinical sample, the agreement between the two systems on the diagnosis of dependence or any opioid use disorder was 0.96 and 0.93, respectively. The agreement between abuse and harmful use was 0.9 and -0.02 with and without regarding hierarchy, respectively. The inter-rater reliability of both DSM-IV and ICD-10 systems for all diagnosis was more than 0.95. The results of the diagnosis of dependence in the two systems had a weak concordance with treatment. The diagnostic criteria of DSM-IV and ICD-10 regarding dependence are very similar and the diagnosis produced by each system is concordant with the other system. However, the two systems have noticeable discrepancies in the diagnosis of abuse and harmful use. The discrepancies result from their conceptual differences and necessitate further revision in the definition of these disorders in the two systems.

No detectable association between frequency of marijuana use and health or healthcare utilization among primary care patients who screen positive for drug use

BACKGROUND

Marijuana is the most commonly used illicit drug, yet its impact on health and healthcare utilization has not been studied extensively.

METHODS

To assess the cross-sectional association between frequency of marijuana use and healthcare utilization (emergency department and hospitalization) and health (comorbidity, health status), we studied patients in an urban primary care clinic who reported any recent (past 3-month) drug use (marijuana, opioids, cocaine, others) on screening. Frequency of marijuana use in the past 3 months was the main independent variable [daily/ almost daily, less than daily and no use (reference group)]. Outcomes assessed were past 3-month emergency department or hospital utilization, the presence of medical comorbidity (Charlson index ≥ 1), and health status with the EuroQol. We used separate multivariable regression models adjusting for age, sex, tobacco and other substance use.

RESULTS

All 589 participants reported recent drug use: marijuana 84 % (29 % daily, 55 % less than daily), cocaine 25 %, opioid 23 %, other drugs 8 %; 58 % reported exclusive marijuana use. Frequency of marijuana use was not significantly associated with emergency department use {adjusted odds ratio [AOR] 0.67, [95 % confidence interval (CI) 0.36, 1.24] for daily; AOR 0.69 [95 % CI 0.40,1.18] for less than daily versus no use}, hospitalization [AOR 0.79 (95 % CI 0.35, 1.81) for daily; AOR 1.23 (95 % CI 0.63, 2.40) for less than daily versus no use], any comorbidity [AOR 0.62, (95 % CI 0.33, 1.18) for daily; AOR 0.67 (95 % CI 0.38, 1.17) for less than daily versus no use] or health status (adjusted mean EuroQol 69.1, 67.8 and 68.0 for daily, less than daily and none, respectively, global p = 0.78).

CONCLUSIONS

Among adults in primary care who screen positive for any recent illicit or non-medical prescription drug use, we were unable to detect an association between frequency of marijuana use and health, emergency department use, or hospital utilization.

Optimal scaling of the CAST and of SDS Scale in a national sample of adolescents

PURPOSE

Psychometric and screening properties of the Cannabis Abuse Screening Test (CAST) and of the Severity Dependence Scale (SDS) were investigated using DSM-IV diagnoses of cannabis dependence (CD) as external criteria. Performance of the SDS and of the CAST were compared.

METHODS

Cross-sectional European School Survey Project on Alcohol and Other Drugs (ESPAD) was carried out in Italy in 2009. The sample consisted of 5787 Italian adolescents aged 15-19 who reported cannabis last year use. Uni-dimensionality, internal reliability, external validity, and optimal scaling of the 6 items for CAST and 5 items for SDS were performed. The Munich Composite International Diagnostic Interview (M-CIDI) was used as a gold standard for DSM-IV diagnoses, and all outputs were assessed by 10-fold cross validation procedure.

RESULTS

Both scales were uni-dimensional and Cronbach's α was 0.74 for SDS and 0.78 for CAST. High and comparable area under curve (AUC) values indicate a good ability of both scales to discriminate between individuals with and without dependence diagnosis. Based on balanced sensitivity and specificity, the optimal cut-off scores for problematic use disorders were 7 for CAST MCA and 4 for SDS MCA. Both CAST and SDS overestimated CD prevalence.

CONCLUSIONS

The CAST and SDS are equally useful for screening for problematic cannabis use disorders. Both clinical and research applications of the scales are possible.

Relationship of substance abuse to dependence in the U.S. general population

OBJECTIVE

The diagnostic categories of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, for substance abuse and dependence are commonly used in clinical work and research studies, but whether abuse and dependence represent two different syndromes has been debated. The purpose of this article is to investigate the relationship of substance abuse and dependence for cannabis, cocaine, stimulants and sedatives among lifetime users of these substances in the National Epidemiologic Survey on Alcohol and Related Conditions, a nationally representative survey conducted in 2001-2002.

METHOD

The multiple indicators multiple causes (MIMIC) model addresses three sets of relationships: those between (1) diagnostic criteria and latent factors, (2) latent factors and covariates, and (3) criteria and covariates. This approach allows for the detection of and compensation for noninvariance of the measurement of criteria across subgroups.

RESULTS

Compared with one-factor models, two-factor models (factors roughly corresponding to abuse and dependence) fit significantly better across all substances, with abuse and dependence factors highly correlated. The MIMIC model indicated that race/ethnicity, age, income, and marital status showed some differential relationships across substance groups, although most covariates showed similar associations to dependence and abuse factors. Noninvariance of criteria measurement by demographic covariates was most pronounced for cannabis abuse and dependence criteria.

CONCLUSIONS

The general relationship of abuse to dependence was consistent across substances. Results were equivocal on the value of retaining separate factors; therefore, investigating the relationships of specific genetic variants and treatment outcomes to dimensional indicators of abuse, dependence, and measures combining these criteria is warranted. Measurement of cannabis abuse and dependence criteria appears most affected by demographic characteristics.

State of the art treatments for cannabis dependence

The treatment of cannabis dependence can be viewed as a cup half empty or half full. On the one hand, few people who might benefit from treatment actually receive it. Among those who undergo treatment in randomized trials, long-term abstinence is achieved by fewer than 20%. Moderate use goals have been associated with decreases in consequences, but the differential impact of such goals on the long-term course of cannabis dependence is unknown. Optimal duration of treatment is unclear, and certain populations, particularly patients with co-occurring disorders, have not been studied adequately. Twelve-step programs are low cost, effective for other substance use disorders, and readily available in most regions of the world. However, their role and efficacy in cannabis dependence has not been examined. Finally, effective pharmacologic treatments are under development, but none have yet been firmly established. On the other hand, psychotherapeutic strategies used to treat other substance use disorders can be effective for cannabis dependence. A recent meta-analysis of psychosocial interventions for illicit substance use disorders found that treatments for cannabis dependence had comparatively larger effect sizes than treatments for other substance use disorders. Combination therapies have proven most effective, particularly those that begin with a motivational intervention, utilize incentives to enhance the commitment to change, and teach behavioral and cognitive copings skills to prevent relapse. Among adolescents, family engagement and collaboration with community stakeholders adds substantial value. Although only 9% of cannabis users develop cannabis dependence, the volume of people who smoke cannabis ensures that the total number of people in need of help is larger than the capacity of substance abuse specialty services. Thus, although efforts to refine and improve the efficacy of treatment interventions continue, innovations that increase the availability and accessibility of treatment are also needed. Computer- and phone-based interventions, social media, and brief interventions that can be implemented in primary care settings are areas that may hold promise for reaching at-risk populations. Adolescents and persons with co-occurring mental illness are at particularly high risk of cannabis dependence, and may suffer disproportionately from cannabis’s adverse effects. As in the treatment of other substance use disorders, there is a need for a continuing care model with long-term follow-up that extends past the periods typically evaluated in treatment studies. Additionally, there is a need for further investigation of genetic underpinnings and endophenotypes underlying cannabis dependence to identify neurobiological mechanisms for targeted intervention. One benefit of the societal focus on cannabis has been a prominent increase in research covering everything from the basic science to public health impact of cannabis. Over the next decade, physicians who provide treatment for individuals with cannabis dependence are likely to see their armamentarium of effective interventions expand, to the ultimate betterment of patients, their families, and society at large.

Analyses related to the development of DSM-5 criteria for substance use related disorders: 3. An assessment of Pathological Gambling criteria

BACKGROUND

The DSM-5 Substance-Related Disorders Work Group proposed to include Pathological Gambling within the current Substance-Related Disorders section. The objective of the current report was to assess four possible sets of diagnostic criteria for Pathological Gambling.

METHODS

Gamblers (N=161) were defined as either Pathological or Non-Pathological according to four classification methods. (a) Option 1: the current DSM-IV criteria for Pathological Gambling; (b) Option 2: dropping the "Illegal Acts" criterion, while keeping the threshold at 5 required criteria endorsed; (c) Option 3: the proposed DSM-5 approach, i.e., deleting "Illegal Acts" and lowering the threshold of required criteria from 5 to 4; (d) Option 4: to use a set of Pathological Gambling criteria modeled on the DSM-IV Substance Dependence criteria. Cronbach's alpha and eigenvalues were calculated for reliability, Phi, discriminant function analyses, correlations and multivariate regression models were performed for validity and kappa coefficients were calculated for diagnostic consistency of each option.

RESULTS

All criteria sets were reliable and valid. Some criteria had higher discriminant properties than others.

CONCLUSION

The proposed DSM-5 criteria in Options 2 and 3 performed well and did not appear to alter the meanings of the diagnoses of Pathological Gambling from DSM-IV. Future work should further explore if Pathological Gambling might be assessed using the same criteria as those used for Substance Use Disorders.

The clinical significance of drug craving

Although drug craving has received considerable research attention over the past several decades, to date there has been no systematic review of the general clinical significance of craving. This paper presents an overview of measurement issues of particular relevance to a consideration of use of craving in clinical settings. The paper then considers the relevance of craving across a broad array of clinical domains, including diagnosis, prognostic utility, craving as an outcome measure, and the potential value of craving as a direct target of intervention. The paper is both descriptive and prescriptive, informed by the current state of the science on craving with recommendations for the definition of craving, assessment practices, future research, and clinical applications. We conclude that craving has considerable utility for diagnosis and as a clinical outcome, and that findings from future research will likely expand the clinical potential of the craving construct in the domains of prognosis and craving as a treatment target.

The 'grass ceiling': limitations in the literature hinder our understanding of cannabis use and its consequences

AIM

To illustrate how limitations in the cannabis literature undermine our ability to understand cannabis-related harms and problems experienced by users and identify users at increased risk of experiencing adverse outcomes of use.

METHOD AND RESULTS

Limitations have been organized into three overarching themes. The first relates to the classification systems employed by researchers to categorize cannabis users, their cannabis use and the assumptions on which these systems are based. The second theme encompasses methodological and reporting issues, including differences between studies, inadequate statistical control of potential confounders, the under-reporting of effect sizes and the lack of consideration of clinical significance. The final theme covers differing approaches to studying cannabis use, including recruitment methods. Limitations related to the nature of the data collected by researchers are discussed throughout, with a focus on how they affect our understanding of cannabis use and users.

CONCLUSIONS

These limitations must be addressed to facilitate the development of effective and appropriately targeted evidence-based public health campaigns, treatment programmes and preventative, early intervention and harm minimization strategies, and to inform cannabis-related policy and legislation.

Entwicklung und Evaluation eines deutschsprachigen Instruments zur Erfassung von Cannabis-Craving (CCS-7)

Zusammenfassung. Theoretischer Hintergrund: Suchtdruck („Craving”) nach Cannabis kann mit einem englischsprachigen Instrument (MCQ) auf vier Dimensionen abgebildet werden. Fragestellung: Ziel war die Entwicklung eines deutschsprachigen Instruments zur Erfassung von Cannabis-Craving sowie die Untersuchung der Zusammenhänge von Craving und demografischen bzw. konsumbezogenen Daten. Methode: Die Kurzversion des MCQ wurde ins Deutsche übersetzt und bei drei Stichproben von Cannabiskonsumenten evaluiert. Demografische Daten und Konsummuster wurden erfasst, sowie die subjektive Einschätzung der Konsumenten ihres aktuellen Suchtdrucks. Ergebnisse: Die Faktorenstruktur des MCQ ließ sich nicht replizieren; es bildeten sich zwei Faktoren, die inhaltlich den Konzepten des Reward- (Belohnungs-) und Relief (Erleichterungs-)-Craving entsprechen. Ein positiver Zusammenhang zwischen Konsumhäufigkeit und Relief-Craving sowie ein negativer Zusammenhang zwischen aktueller Abstinenzzeit und Reward-Craving zeigte sich. Beide Dimensionen korrelierten mit der subjektiven Einschätzung des Craving. Schlussfolgerungen: Cannabis-Craving kann als Konstrukt mit mindestens zwei Dimensionen betrachtet werden. Diese können mit dem CCS-7 zuverlässig erfasst werden.

Cannabis dimensionality: dependence, abuse and consumption

AIMS

Genetic research on substance use disorders usually defines phenotypes as a binary diagnosis, resulting in a loss of information if the disorder is inherently dimensional. The DSM-IV criteria for drug dependence were based on a theoretically dimensional (linear) model. Considerable investigation has been conducted on DSM-IV alcohol criteria, but less is known about the dimensionality of DSM-IV cannabis criteria for abuse and dependence. The aim of this study is to assess whether DSM-IV cannabis dependence (including withdrawal) and abuse criteria fit a linear measure of severity and whether a consumption criterion adds linearly to severity.

DESIGN/SETTING/PARTICIPANTS/MEASUREMENTS

Participants were 8172 in the National Epidemiologic Survey on Alcohol and Related Conditions who had ever used cannabis. Wald statistics were used to test whether categorical, dimensional or hybrid forms best fit the data. We examined the following as criterion sets: (1) dependence; (2) dependence and abuse; and (3) dependence, abuse and frequency of use. Validating variables included family history of drug problems, early onset of cannabis use, and antisocial personality disorder.

FINDINGS

For cannabis dependence, no evidence was found for categorical or hybrid models; Wald tests indicated that models representing the seven DSM-IV dependence criteria as a linear severity measure best described the association between the criteria and validating variables. However, significant differences from linearity occurred after adding the four cannabis abuse criteria (p=0.03) and the use indicator (p=0.01) for family history and antisocial personality disorder.

CONCLUSION

With ample power to detect non-linearity, cannabis dependence was shown to form an underlying continuum of severity. However, adding abuse criteria, with and without a measure of consumption, resulted in a model that differed significantly from linearity for two of the three validating variables.

Continuous, categorical and mixture models of DSM-IV alcohol and cannabis use disorders in the Australian community

AIMS

To apply item response mixture modelling (IRMM) to investigate the viability of the dimensional and categorical approaches to conceptualizing alcohol and cannabis use disorders.

DESIGN

A cross-sectional survey assessing substance use and DSM-IV substance use disorders.

SETTING AND PARTICIPANTS

A household survey of a nationally representative sample of 10,641 Australia adults (aged 18 years or older).

MEASUREMENTS

Trained survey interviewers administered a structured interview based on the Composite International Diagnostic Interview (CIDI).

FINDINGS

Of the 10,641 Australian adults interviewed, 7746 had drunk alcohol in the past 12 months and 722 had used cannabis. There was no improvement in fit for categorical latent class nor mixture models combining continuous and categorical parameters compared to continuous factor analysis models. The results indicated that both alcohol and cannabis problems can be considered as dimensional, with those with the disorder arrayed along a dimension of severity.

CONCLUSIONS

A single factor accounts for more variance in the DSM-IV alcohol and cannabis use criteria than latent class or mixture models, so the disorders can be explained most effectively by a dimensional score.

Harmonisation of ICD-11 and DSM-V: opportunities and challenges

BACKGROUND

Differences in the ICD-10 and DSM-IV definitions for the same disorder impede international communication and research efforts. The forthcoming parallel development of DSM-V and ICD-11 offers an opportunity to harmonise the two classifications.

AIMS

This paper aims to facilitate the harmonisation process by identifying diagnostic differences between the two systems.

METHOD

DSM-IV-TR criteria sets and the ICD-10 Diagnostic Criteria for Research were compared and categorised into those with identical definitions, those with conceptually based differences and those in which differences are not conceptually based and appear to be unintentional.

RESULTS

Of the 176 criteria sets in both systems, only one, transient tic disorder, is identical. Twenty-one per cent had conceptually based differences and 78% had non-conceptually based differences.

CONCLUSIONS

Harmonisation of criteria sets, especially those with non-conceptually based differences, should be prioritised in the DSM-V and ICD-11 development process. Prior experience with the DSM-IV and ICD-10 harmonisation effort suggests that for the process to be successful steps should be taken as early as possible.

An item response theory modeling of alcohol and marijuana dependences: a National Drug Abuse Treatment Clinical Trials Network study

OBJECTIVE

The aim of this study was to examine psychometric properties of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), diagnostics criteria for alcohol and marijuana dependences among 462 alcohol users and 311 marijuana users enrolled in two multisite trials of the National Drug Abuse Treatment Clinical Trials Network.

METHOD

Diagnostic questions were assessed by the DSM-IV checklist. Data were analyzed by the item response theory and the multiple indicators-multiple causes method procedures.

RESULTS

Criterion symptoms of alcohol and marijuana dependences exhibited a high level of internal consistency. All individual symptoms showed good discrimination in distinguishing alcohol or marijuana users between high and low severity levels of the continuum. In both groups, "withdrawal" appeared to measure the most severe symptom of the dependence continuum. There was little evidence of measurement nonequivalence in assessing symptoms of dependence by gender, age, race/ethnicity, and educational level.

CONCLUSIONS

These findings highlight the clinical utility of the DSM-IV checklist in assessing alcohol- and marijuana dependence syndromes among treatment-seeking substance users.

Behavioural and dopaminergic alterations induced by a low dose of WIN 55,212-2 in a conditioned place preference procedure

AIMS

This study investigated the role of the cannabinoid CB1 receptor agonist, WIN 55,212-2, on motor activity. Subsequently, the effects of a low, stimulatory dose of WIN 55,212-2 and cocaine, as a positive control, were evaluated using a conditioned place preference (CPP) procedure. Upon completion of CPP, in rats that had been treated with WIN 55,212-2, dopaminergic status and spontaneous and d-amphetamine-induced motor activity were assessed.

MAIN METHODS

Sprague-Dawley rats were evaluated for habituated motor activity following WIN 55,212-2 (0, 0.1, 0.3, 1 mg/kg, i.p.) administration. A stimulatory dose of WIN 55,212-2 (0.1 mg/kg, i.p.) and cocaine (20 mg/kg, i.p.) was selected to assess CPP behaviour. Upon completion of CPP, in one group, tissue levels of dopamine and its metabolites were measured in distinct brain regions (dorsal striatum, nucleus accumbens, prefrontal cortex, amygdala, hippocampus) using High Performance Liquid Chromatography with electrochemical detection. In another group, spontaneous and D-amphetamine-induced motor activity was evaluated in an open-field apparatus.

KEY FINDINGS

The lowest dose of WIN 55,212-2 increased motor activity but did not produce CPP. As expected, cocaine induced clear CPP. Dopaminergic status was increased in a region-specific way and motor activity was enhanced following a challenge of D-amphetamine in rats that had been administered with WIN 55,212-2 during conditioning.

SIGNIFICANCE

A stimulatory effect of WIN 55,212-2 on motor activity was not accompanied by place preference. Upon completion of the CPP procedure, this dose was found to induce region-specific hyperdopaminergia along with a greater sensitivity to a subsequent challenge dose of D-amphetamine.

The reliability of self-reported cannabis abuse, dependence and withdrawal symptoms: multisite study of differences between general population and treatment groups

In NIDA-funded studies, 739 cannabis users were interviewed twice, one week apart, in St. Louis, Miami, and Sydney. To examine differences in reliability of DSM-IV cannabis abuse and dependence criteria, including 19 withdrawal symptoms, the sample was dichotomized by treatment status, GEN POP (n=416) and TX (n=278). GEN POP had good to excellent reliability for abuse criteria (kappa=.56 to .86); TX was similarly reliable (kappa=.58 to .82). The most reliable abuse criterion among both groups was "legal problems"; the least reliable was "failure to fulfill major role obligations". The reliability of dependence criteria revealed similar patterns, with GEN POP (kappa=.49 to .74) and TX (kappa=.44 to .73) being equally reliable. The most reliable dependence criterion for both groups was "tolerance"; the least reliable was "continued use despite knowledge of physical or psychological harm". Although not mentioned in the DSM-IV for cannabis, withdrawal symptoms (especially plausible ones) were commonly and reliably reported. These analyses are important to verify the harms of cannabis, including withdrawal, as well as confirming the reliability of the criteria.

DSM-IV criteria-based clinical subtypes of cannabis use disorders: results from the National Epidemiological Survey on Alcohol and Related Conditions (NESARC)

Prior research documented high homogeneity of alcohol use disorders (AUDs) as clinical entities. However, it is unknown whether this finding extends to other substance use disorders. We investigated this by examining the prevalence of all possible DSM-IV criteria-based clinical subtypes of current and lifetime cannabis use disorders in the general population. The number of possible (i.e., theoretical) clinical subtypes of cannabis abuse and dependence based on different combinations of the DSM-IV criteria was calculated using the combinatorial function. This number was compared with the subtypes actually observed in the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a large U.S. national sample (N=43,093). Clinical and demographic correlates of the subtypes were examined with chi2 tests whose target population was the United States civilian non-institutionalized population. All DSM-IV cannabis abuse and dependence criteria were assessed with the Alcohol Use Disorder and Associated Disabilities Interview Schedule-DSM-IV Version (AUDADIS-IV). Of all possible cannabis dependence subtypes, 29 (69%) were observed in the 12-month timeframe, and 41 (98%) in the lifetime timeframe. The corresponding numbers of subtypes for cannabis abuse were 12 (75%), current and 15 (100%), lifetime. These findings suggest that, in contrast to alcohol disorders, cannabis use disorders were highly heterogeneous. Future research should investigate whether there are differences in the course and treatment response of these clinical subtypes of cannabis use disorders, and the heterogeneity of other substance use disorders.

Item response theory analysis of DSM-IV cannabis abuse and dependence criteria in adolescents

OBJECTIVE

To examine three aspects of adolescent cannabis problems: do DSM-IV cannabis abuse and dependence criteria represent two different levels of severity of substance involvement, to what degree do each of the 11 abuse and dependence criteria assess adolescent cannabis problems, and do the DSM-IV items function similarly across different adolescent populations?

METHOD

We examined 5,587 adolescents ages 11 to 19, including 615 youths in treatment for substance use disorders, 179 adjudicated youths, and 4,793 youths from the community. All of the subjects were assessed with a structured diagnostic interview. Item response theory was used to analyze symptom endorsement patterns.

RESULTS

Abuse and dependence criteria were not found to represent different levels of severity of problem cannabis use in any of the samples. Among the 11 abuse and dependence criteria, problems cutting down and legal problems were the least informative for distinguishing problem users. Two dependence criteria and three of the four abuse criteria indicated different severities of cannabis problems across samples.

CONCLUSIONS

We found little evidence to support the idea that abuse and dependence are separate constructs for adolescent cannabis problems. Furthermore, certain abuse criteria may indicate severe substance problems, whereas specific dependence items may indicate less severe problems. The abuse items in particular need further study. These results have implications for the refinement of the current substance use disorder criteria for DSM-V.

The latent structure of marijuana and cocaine use disorders: results from the National Longitudinal Alcohol Epidemiologic Survey (NLAES)

To better understand the underlying concepts of substance dependence and abuse, the present study examines the factor structure of DSM-IV lifetime criteria for cannabis and cocaine use disorders. Data for this study were drawn from the National Longitudinal Alcohol Epidemiologic Survey (NLAES), a large nationally representative U.S. sample aged 18 years and older. Exploratory factor analysis (EFA) examined the factor structure for each substance and the factors were related to background covariates using latent variable modeling techniques. Separate analyses were conducted for lifetime marijuana and cocaine users. A two-factor solution was identified for each substance and was similar to DSM-IV abuse and dependence. The factors were highly correlated for both cannabis (r=0.73) and cocaine (r=0.77). Background variables accounted only for a modest amount of factor variance. In conjunction with the findings in alcohol use disorders, these results support the use of consistent criteria across substances in DSM-IV and ICD-10, and suggest that the consistent finding of two correlated factors across substances needs to be better understood.

Psychometric properties of DSM assessments of illicit drug abuse and dependence: results from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC)

BACKGROUND

DSM-IV criteria for illicit drug abuse and dependence are largely based on criteria developed for alcohol use disorders and there is a lack of research evidence on the psychometric properties of these symptoms when applied to illicit drugs.

METHOD

This study utilizes data on abuse/dependence criteria for cannabis, cocaine, stimulants, sedatives, tranquilizers, opiates, hallucinogens and inhalants from the National Epidemiological Survey on Alcohol and Related Conditions (NESARC, n=43 093). Analyses included factor analysis to explore the dimensionality of illicit drug abuse and dependence criteria, calculation of item difficulty and discrimination within an item response framework and a descriptive analysis of 'diagnostic orphans': individuals meeting criteria for 1-2 dependence symptoms but not abuse. Rates of psychiatric disorders were compared across groups.

RESULTS

Results favor a uni-dimensional construct for abuse/dependence on each of the eight drug classes. Factor loadings, item difficulty and discrimination were remarkably consistent across drug categories. For each drug category, between 29% and 51% of all individuals meeting criteria for at least one symptom did not receive a formal diagnosis of either abuse or dependence and were therefore classified as 'orphans'. Mean rates of disorder in these individuals suggested that illicit drug use disorders may be more adequately described along a spectrum of severity.

CONCLUSIONS

While there were remarkable similarities across categories of illicit drugs, consideration of item difficulty suggested that some alterations to DSM regarding the relevant severity of specific abuse and dependence criteria may be warranted.

A genome-wide scan for loci influencing adolescent cannabis dependence symptoms: evidence for linkage on chromosomes 3 and 9

OBJECTIVE

Cannabis is the most frequently abused illicit substance among adolescents and young adults. Genetic risk factors account for part of the variation in the development of cannabis dependence symptoms; however, no linkage studies have been performed for cannabis dependence symptoms. This study aimed to identify such loci.

METHOD

Three hundred and twenty-four sibling pairs from 192 families were assessed for cannabis dependence symptoms. Probands (13-19 years of age) were recruited from consecutive admissions to substance abuse treatment facilities. The siblings of the probands ranged in age from 12 to 25 years. A community-based sample of 4843 adolescents and young adults was utilized to define an age- and sex-corrected index of cannabis dependence vulnerability. DSM-IV cannabis dependence symptoms were assessed in youth and their family members with the Composite International Diagnostic Instrument-Substance Abuse Module. Siblings and parents were genotyped for 374 microsatellite markers distributed across the 22 autosomes (average inter-marker distance=9.2cM). Cannabis dependence symptoms were analyzed using Merlin-regress, a regression-based method that is robust to sample selection.

RESULTS

Evidence for suggestive linkage was found on chromosome 3q21 near marker D3S1267 (LOD=2.61), and on chromosome 9q34 near marker D9S1826 (LOD=2.57).

CONCLUSIONS

This is the first reported linkage study of cannabis dependence symptoms. Other reports of linkage regions for illicit substance dependence have been reported near 3q21, suggesting that this region may contain a quantitative trait loci influencing cannabis dependence and other substance use disorders.

Factor and item-response analysis DSM-IV criteria for abuse of and dependence on cannabis, cocaine, hallucinogens, sedatives, stimulants and opioids

AIMS

This paper explored, in a population-based sample of males, the factorial structure of criteria for substance abuse and dependence, and compared qualitatively the performance of these criteria across drug categories using item-response theory (IRT).

DESIGN

Marginal maximum likelihood was used to explore the factor structure of criteria within drug classes, and a two-parameter IRT model was used to determine how the difficulty and discrimination of individual criteria differ across drug classes.

PARTICIPANTS

A total of 4234 males born from 1940 to 1974 from the population-based Virginia Twin Registry were approached to participate.

MEASUREMENTS

DSM-IV drug use, abuse and dependence criteria for cannabis, sedatives, stimulants, cocaine and opiates.

FINDINGS

For each drug class, the pattern of endorsement of individual criteria for abuse and dependence, conditioned on initiation and use, could be best explained by a single factor. There were large differences in individual item performance across substances in terms of item difficulty and discrimination. Cocaine users were more likely to have encountered legal, social, physical and psychological consequences.

CONCLUSIONS

The DSM-IV abuse and dependence criteria, within each drug class, are not distinct but best described in terms of a single underlying continuum of risk. Because individual criteria performed very differently across substances in IRT analyses, the assumption that these items are measuring equivalent levels of severity or liability with the same discrimination across different substances is unsustainable. Compared to other drugs, cocaine usage is associated with more detrimental effects and negative consequences, whereas the effects of cannabis and hallucinogens appear to be less harmful. Implications for other drug classes are discussed.

Does gender contribute to heterogeneity in criteria for cannabis abuse and dependence? Results from the national epidemiological survey on alcohol and related conditions

Previous research has noted that a unidimensional latent construct underlies criteria for cannabis abuse and dependence. However, no study to date has explored whether gender contributes to heterogeneity in the latent abuse and dependence construct and furthermore, whether after accounting for differences in the mean scores of abuse and dependence across genders, there is any evidence for heterogeneity in the individual abuse and dependence criteria. The present study utilizes data on criteria for cannabis abuse and dependence from a large, nationally representative sample (National Epidemiological Survey on Alcohol and Related Conditions) of 8172 lifetime cannabis users to investigate whether gender contributes to heterogeneity in the underlying construct of cannabis abuse and dependence, and in each individual criterion as well. Analyses, all of which were conducted in MPlus, included factor analysis, as well as MIMIC and multiple-group models for an examination of dimensionality and gender heterogeneity, respectively. Results favor a unidimensional construct for cannabis abuse/dependence, as seen in prior research. We also identify two abuse (legal and hazard) and two dependence (quit and problems) criteria, which show significant gender heterogeneity with the abuse criteria exhibiting higher thresholds in women and the dependence criteria in men. We conclude that the criteria that serve as indicators of DSM-IV cannabis abuse and dependence do not function identically in men and women and that certain criteria (e.g. hazardous use) require further refinement.

Are specific dependence criteria necessary for different substances: how can research on cannabis inform this issue?

AIMS

Research on cannabis dependence is used to comment on the similarities and differences among the substance dependence disorders, and to address the issue of whether specific versus generic substance dependence diagnostic criteria might offer the most fruitful approach to diagnosis. If cannabis dependence can be diagnosed and characterized adequately using the extant generic Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) dependence criteria, then one could argue that these diagnostic guidelines are valid and of high utility for substances with more well-accepted dependence syndromes.

METHODS

A brief, selective critical review of research on cannabis withdrawal and on the validity and internal consistency of cannabis dependence as assessed via DSM criteria for cannabis dependence was performed.

RESULTS

Findings from these reports indicate that cannabis dependence is much more similar to than different from other types of substance dependence, even with regard to withdrawal. The generic DSM-IV dependence criteria can be applied fairly well to cannabis, and yield findings similar to that observed with other substance dependence disorders. However, across substances, the generic criteria may not discriminate cases in a manner consistent with the underlying constructs of abuse and dependence, and cross-substance differences probably exist in the general dependence severity level and specific symptom profiles.

CONCLUSIONS

The use of generic DSM-IV criteria appears to work as well for cannabis dependence as for other substances, yet the more important question might be as to whether we can do better by developing more sophisticated generic criteria or by using substance specific criteria.

Pothead or pot smoker? A taxometric investigation of cannabis dependence

BACKGROUND

Taxometric methods were used to discern the latent structure of cannabis dependence. Such methods help determine if a construct is categorical or dimensional. Taxometric analyses (MAXEIG and MAMBAC) were conducted on data from 1,474 cannabis-using respondents to the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Respondents answered questions assessing DSM-IV criteria for cannabis dependence.

RESULTS

Both taxometric methods provided support for a dimensional structure of cannabis dependence.

CONCLUSION

Although the MAMBAC results were not entirely unequivocal, the majority of evidence favored a dimensional structure of cannabis dependence.

A comparison of the latent class structure of cannabis problems among adult men and women who have used cannabis repeatedly

BACKGROUND

Little empirical evidence exists to determine if there are alternative classification schemes for cannabis abuse and dependence beyond the definitions provided by Diagnostic and Statistical Manual (DSM) criteria. Current evidence is not conclusive regarding gender differences for cannabis use, abuse and dependence. It is not known if symptom profiles differ by gender.

METHODS

Latent class analysis (LCA) was used to assess whether cannabis abuse and dependence symptom patterns suggest a severity spectrum or distinct subtypes and to test whether symptom patterns differ by gender. Data from 3312 men and 2509 women in the National Longitudinal Alcohol Epidemiologic Survey (NLAES) who had used cannabis 12 + times life-time were included in the present analyses. The comparability of the solutions for men and women was examined through likelihood ratio chi(2) tests.

RESULTS

Based on the Bayesian information criterion and interpretability, a four-class solution was selected, and the classes were labeled as 'unaffected/mild hazardous use', 'hazardous use/abuse', 'abuse/moderate dependence' and 'severe abuse/dependence'. The solutions were generally suggestive of a severity spectrum. Compared to men, women were more likely to be in the 'unaffected/mild hazardous use' class and less likely to be in the 'abuse/moderate dependence' or 'severe abuse/dependence' classes. The results were generally similar for men and women. However, men had consistently and substantially higher endorsements of hazardous use than women, women in the 'abuse/moderate dependence' class had moderately higher rates for four dependence symptoms, and women in two of the classes were more likely to endorse withdrawal.

CONCLUSION

Our findings generally support the severity dimension for DSM-IV cannabis abuse and dependence symptomatology for both men and women. While our results indicate that public health messages may have generic and not gender-specific content, treatment providers should focus more effort on reducing hazardous use in men and alleviating withdrawal in women.

The genetic epidemiology of cannabis use, abuse and dependence

AIMS

The genetic etiology of cannabis use, abuse and dependence has elicited significant interest from genetic epidemiologists.

METHODS

Genetically informative studies, including family, twin and adoption studies that have examined the role of genetic and environmental influences on the various stages of cannabis involvement, and the genetic relationship between cannabis, licit drugs and other hard drugs, are reviewed.

RESULTS

Findings across a number of such studies have indicated that there is a genetic basis to each stage of cannabis involvement although a proportion of the genetic factors influencing individual stages may be specific to that stage. Multivariate analyses that explore the association between cannabis and licit (alcohol and tobacco) as well as hard drugs (e.g. cocaine, opioids), using multiple methodological strategies, suggest the role of common genetic and environmental influences influencing the liability to cannabis and other drug involvement.

CONCLUSIONS

The substantial evidence for the heritability of cannabis use, abuse and dependence underscore the importance of linkage and association studies that aim to find genes of etiologic significance.

Substance use, dependence and treatment seeking in the United States and Australia: a cross-national comparison

AIMS

To compare the prevalence of alcohol and drug use, dependence and treatment seeking in the United States of America and Australia.

DESIGN

Two cross-sectional national surveys assessing substance use and DSM-IV substance dependence in the USA and Australia.

SETTING AND PARTICIPANTS

Age-matched cohorts (18-54 years old) were selected from nationally representative Australian (National Survey of Mental Health and Well-being, 1997, n=7570) and American (National Comorbidity Survey, 1992, n=7423) household surveys.

MEASUREMENTS

Both studies utilised a structured interview based on the Composite International Diagnostic Interview (CIDI).

FINDINGS

The 12-months prevalence of alcohol use was substantially higher in Australia (77.2%) than in the U.S. (46.3%) and the rates of alcohol dependence were also higher in Australia, although rates of alcohol dependence conditional on use were similar (6.8 and 6.5%, respectively). In contrast, although rates of use of drugs were similar in the two countries, rates of drug dependence and the probability of dependence conditional on use were higher in Australia than in the U.S. Importantly, the absence of significant interactions between correlates of alcohol and drug use disorders and country indicated that the influence of these factors was consistent across the two countries.

CONCLUSIONS

Despite relatively similar cultural influences in Australia and the U.S. interesting cross-national differences emerged in the use of alcohol and drug dependence among those who used drugs and treatment seeking among people diagnosed with dependence. The cross-national generalizability of the associations between common correlates and rates of alcohol and drug use and dependence indicates that similar process of vulnerability to dependence may be operating in the two countries. Future research could usefully exploit these cross-national differences to help elucidate the cultural and structural factors influencing drug use, the development of dependence and treatment seeking.

Comorbidity: cannabis and complexity

Cannabis is one of the most commonly used illicit drugs, and its effects have traditionally been seen as less harmful than outcomes associated with the highly prevalent use of alcohol and other illicit substances (e.g., cocaine and amphetamines), and injecting drugs. Consequently, less attention has been focused on developing and evaluating interventions in this area. However, current research supports the idea that cannabis does pose a number of acute and chronic health risks to the individual and to society. The authors review findings concerning the physiological and neurological effects of cannabis, prevalence of use, and studies concerning its possible role as a "gateway" drug. Diagnostic criteria for cannabis dependence and abuse are discussed, with a focus on whether a cannabis withdrawal syndrome exists and if so how it can be diagnosed. There is strong support for a link between cannabis and the development and exacerbation of psychosis and other mental health conditions (e.g., anxiety, depression). Further research is needed to determine the underlying neurochemical processes and their possible contribution to etiology, as well as the social factors that contribute to the increasing use of cannabis by young people. In addition there is a need for systematic evaluation using randomized controlled trials to determine effective prevention and treatment strategies. A number of public health programs that address cannabis use are reviewed along with available evidence for their effectiveness.

A prototype screening instrument for cannabis use disorder: the Cannabis Use Disorders Identification Test (CUDIT) in an alcohol-dependent clinical sample

The Cannabis Use Disorders Identification Test (CUDIT) was used for the first time as part of a randomized controlled trial for brief interventions in mild to moderate alcohol-dependent out-patients. This sample may be seen as a population at increased risk of cannabis use disorder. The CUDIT was developed by modifying the Alcohol Use Disorders Identification Test (AUDIT). The ability of the CUDIT to accurately screen for cannabis abuse or dependence was examined in the portion of the sample who reported some cannabis use over the preceding 6 months (n=53), as was self-reported frequency of cannabis use in the preceding 6 months. The CUDIT was superior to the frequency measure, achieving positive predictive power of 84.6% and sensitivity of 73.3% at a cut-off of 8, compared to positive predictive power of 81.8% and sensitivity of 60.0% for 80 or more cannabis use-days. These results indicate the viability of a screening measure for identifying cannabis use disorder in at risk populations.

Cannabis dependence and mental health perception amongst people diverted by police after arrest for cannabis-related offending behaviour in Australia

BACKGROUND

Use of cannabis and other mind-altering drugs may be associated with violence or other offending behaviours. In many countries mere possession of the drug may be sufficient to lead to a criminal conviction and, therefore, a criminal record. Recent legal and policy reforms in Australia have led to development of cannabis diversion programmes.

OBJECTIVE

To describe substance misuse patterns and health perception in a consecutive series of young people in Queensland who were spared a criminal record because of a cannabis diversion scheme.

METHOD

Between 9 July 2001 and 24 August 2004, 640 men and 187 women were diverted through the Queensland Illicit Drug Diversion Initiative (QIDDI) for treatment at a hospital alcohol and drug service. In this cross-sectional study of their drug use history, participants also completed the Severity of Dependence Scale (SDS) for cannabis and the General Health Questionnaire-28 (GHQ-28).

RESULTS

Almost 60% of participants were cannabis dependent (as determined by the SDS). Polysubstance use was also more prevalent amongst dependent participants. Self-reported health (GHQ-28) was poorer than expected from Australian normative data, and worse if participants were cannabis dependent. Applying the GHQ-28 threshold for psychiatric case identification (caseness), cannabis dependent participants had significantly higher level of caseness across all subscales of somatic concerns, anxiety, social dysfunction and depression. Dependent women registered the highest proportion of psychopathology, particularly anxiety and social dysfunction.

CONCLUSIONS

Young cannabis users in Queensland who come into contact with the police are more likely than not to be dependent on the drug. Their high levels of psychopathology suggest that they are better placed in healthcare rather than the criminal justice system, and that appropriately responsive mental healthcare programmes are needed.

The good and the bad effects of (−) trans-delta-9-tetrahydrocannabinol (Δ9-THC) on humans

This review analyses the therapeutic usefulness of Delta(9)-tetrahydrocannabinol and its potential to induce adverse reactions on humans. During the last 30 years an enormous amount of research was carried out resulting in the disclosure of the cannabinoid system in Central Nervous System, with its CB(1) and CB(2) receptors, and the agonist anandamide. Under the clinical point of view, Delta(9)-THC produces some therapeutic benefits which are beyond reasonable doubt. Thus, the effects on nausea/emesis due to cancer chemotherapy, as appetite promoter, on some painful conditions and on symptoms of multiple sclerosis are clearly demonstrated. Delta(9)-THC is not devoid of ill effects. On the cognitive domain it impairs the human capacity to discriminate time intervals and space distances, vigilance, memory and the performance for mental work. On the psychic area Delta(9)-THC may induce unpleasant reactions such as disconnected thoughts, panic reactions, disturbing changes in perception, delusions and hallucinatory experiences. However, the long term effects on the psyche and cognition are not known as there are no reports of prolonged use of Delta(9)-THC. Actually, it has been proposed by WHO that Delta(9)-THC should be rescheduled to schedule IV of the United Nations Convention on Psychotropic Drugs, as it does not constitute a substantial risk to public health and its abuse is rare if at all.

Adverse effects of cannabis on health: an update of the literature since 1996

Recent research has clarified a number of important questions concerning adverse effects of cannabis on health. A causal role of acute cannabis intoxication in motor vehicle and other accidents has now been shown by the presence of measurable levels of Delta(9)-tetrahydrocannabinol (THC) in the blood of injured drivers in the absence of alcohol or other drugs, by surveys of driving under the influence of cannabis, and by significantly higher accident culpability risk of drivers using cannabis. Chronic inflammatory and precancerous changes in the airways have been demonstrated in cannabis smokers, and the most recent case-control study shows an increased risk of airways cancer that is proportional to the amount of cannabis use. Several different studies indicate that the epidemiological link between cannabis use and schizophrenia probably represents a causal role of cannabis in precipitating the onset or relapse of schizophrenia. A weaker but significant link between cannabis and depression has been found in various cohort studies, but the nature of the link is not yet clear. A large body of evidence now demonstrates that cannabis dependence, both behavioral and physical, does occur in about 7-10% of regular users, and that early onset of use, and especially of weekly or daily use, is a strong predictor of future dependence. Cognitive impairments of various types are readily demonstrable during acute cannabis intoxication, but there is no suitable evidence yet available to permit a decision as to whether long-lasting or permanent functional losses can result from chronic heavy use in adults. However, a small but growing body of evidence indicates subtle but apparently permanent effects on memory, information processing, and executive functions, in the offspring of women who used cannabis during pregnancy. In total, the evidence indicates that regular heavy use of cannabis carries significant risks for the individual user and for the health care system.

Role of endocannabinoid system in mental diseases

In the last decade, a large number of studies using Delta9-tetrahydrocannabinol (THC), the main active principle derivative of the marijuana plant, or cannabinoid synthetic derivatives have substantially contributed to advance the understanding of the pharmacology and neurobiological mechanisms produced by cannabinoid receptor activation. Cannabis has been historically used to relieve some of the symptoms associated with central nervous system disorders. Nowadays, there are anecdotal evidences for the use of cannabis in many patients suffering from multiple sclerosis or chronic pain. Following the historical reports of the use of cannabis for medicinal purposes, recent research has highlighted the potential of cannabinoids to treat a wide variety of clinical disorders. Some of these disorders that are being investigated are pain, motor dysfunctions or psychiatric illness. On the other hand, cannabis abuse has been related to several psychiatric disorders such as dependence, anxiety, depression, cognitive impairment, and psychosis. Considering that cannabis or cannabinoid pharmaceutical preparations may no longer be exclusively recreational drugs but may also present potential therapeutic uses, it has become of great interest to analyze the neurobiological and behavioral consequences of their administration. This review attempts to link current understanding of the basic neurobiology of the endocannabinoid system to novel opportunities for therapeutic intervention and its effects on the central nervous system.

Possible age-associated bias in reporting of clinical features of drug dependence: epidemiological evidence on adolescent-onset marijuana use

AIMS

To probe recent evidence on apparent excess occurrence of marijuana dependence when marijuana smoking starts in adolescence.

DESIGN AND PARTICIPANTS

A national sample of recent-onset marijuana users was identified within public data files of the National Household Survey on Drug Abuse (NHSDA), 1995-98 (1,866 adolescents and 762 adults).

MEASUREMENTS

Marijuana dependence was assessed via seven standardized questions about its clinical features, such as being unable to cut down. Multivariate response models (GLM/GEE and MIMIC) were used to evaluate adolescent excess risk and possible item biases.

FINDINGS

Among people who had just started to use marijuana, clinical features of marijuana dependence occurred twice as often among adolescents compared to adults, even with statistical adjustment for other covariates (P < 0.01 from GLM/GEE). MIMIC analyses suggest that adolescent-onset users have somewhat higher levels of marijuana dependence, and they also provide evidence of age-associated response bias for some but not all clinical features of marijuana dependence. That is, even with level of marijuana dependence held constant, adolescent recent-onset users were more likely than adults to report being unable to cut down (P = 0.01) and tolerance (P = 0.029).

CONCLUSION

Nosologic, methodological and substantive reasons for observed age-related excess in occurrence of marijuana dependence problems among early onset users deserve more attention in future research.

Cannabis use is not associated with the development of psychosis in an 'ultra' high-risk group

BACKGROUND

The association between cannabis use and the development of a first psychotic episode was studied in a group of 100 young people identified as being at very high risk for the onset of psychosis.

METHOD

The 'ultra' high risk cohort was identified by the presence of subthreshold psychotic symptoms, or a combination of first-degree relative with a psychotic disorder and recent functional decline. Thirty-two per cent of the cohort developed an acute psychotic episode over the 12-month period after recruitment. As a component of a larger research study, the level of cannabis use by participants in the year prior to enrollment in the study was assessed at intake.

RESULTS

Cannabis use or dependence in the year prior to recruitment to this study was not associated with a heightened risk of developing psychosis over the following 12-month period and therefore did not appear to contribute to the onset of a psychotic disorder.

CONCLUSION

The results of this study suggest that cannabis use may not play an integral role in the development of psychosis in a high-risk group. While this study does not support a role for cannabis in the development of first-episode psychosis, we cannot conclude that cannabis use should be completely ignored as a candidate risk factor for onset of psychosis. A number of weaknesses of the study (the low level of cannabis use in the current sample, the lack of monitoring of cannabis use after intake) suggest that it may be premature to dismiss cannabis use as a risk factor for the development of psychosis and further research is urged in this area.

The structure of cannabis dependence in the community

BACKGROUND

Cannabis is the most widely used illicit drug in developed countries, and has a significant impact on mental and physical health in the general population. However, the validity of common diagnostic schemes and their applicability to cannabis abuse and dependence is poorly understood. This paper describes a confirmatory factor analysis of the DSM-IV cannabis abuse and dependence criteria, using general population data.

METHODS

Data from cannabis users (n=722) were obtained from a cross-sectional study of a large and representative sample of the Australian general population. The DSM-IV criteria for cannabis abuse and dependence were assessed using the CIDI-AUTO.

RESULTS

Approximately, one in 12 Australians (7.1%) had used cannabis more than five times in the past 12 months and 56.5% of these reported at least one DSM-IV cannabis abuse or dependence criteria. Within the adult population, 2.2% met criteria for a cannabis use disorder (0.7% abuse and 1.5% dependence). Confirmatory factor analysis indicated that both a one- and two-factor model for cannabis use disorder provided an adequate fit to the data. However, the estimated correlation between the abuse and dependence factors in the two-factor model was extremely high (0.99).

CONCLUSIONS

A one-factor model provided the most parsimonious model of the cannabis abuse and dependence criteria.