David J. Allsop

Computer‐delivered interventions for alcohol and tobacco use: a meta‐analysis

AIMS To quantify the overall effectiveness of computer-delivered interventions for alcohol and tobacco use. METHODS Meta-analysis of 42 effect sizes from randomized controlled trials, based on the responses of 10 632 individuals. RESULTS The weighted average effect size (d) was 0.20, P < 0.001. While lower effect sizes were associated with studies addressing tobacco use (d = 0.14) this may well reflect differences in the types of outcome measure used. Effect sizes did not vary significantly as a function of treatment location, inclusion of entertaining elements, provision of normative feedback, availability of a discussion feature, number of treatment sessions, emphasis on relapse prevention, level of therapist involvement or follow-up period. CONCLUSION Findings of the meta-analysis suggest that minimal contact computer-delivered treatments that can be accessed via the internet may represent a cost-effective means of treating uncomplicated substance use and related problems.

The Cannabis Withdrawal Scale development: patterns and predictors of cannabis withdrawal and distress.

BACKGROUND Rates of treatment seeking for cannabis are increasing, and relapse is common. Management of cannabis withdrawal is an important intervention point. No psychometrically sound measure for cannabis withdrawal exists, and as a result treatment developments cannot be optimally targeted. The aim is to develop and test the psychometrics of the Cannabis Withdrawal Scale and use it to explore predictors of cannabis withdrawal. METHODS A volunteer sample of 49 dependent cannabis users provided daily scores on the Cannabis Withdrawal Scale during a baseline week and 2 weeks of abstinence. RESULTS Internal reliability (Cronbachs alpha=0.91), test-retest stability (average intra-class correlation=0.95) and content validity analysis show that the Cannabis Withdrawal Scale has excellent psychometric properties. Nightmares and/or strange dreams was the most valid item (Wald χ²=105.6, P<0.0001), but caused relatively little associated distress (Wald χ²=25.11, P=0.03). Angry outbursts were considered intense (Wald χ²=73.69, P<0.0001) and caused much associated distress (Wald χ²=45.54, P<0.0001). Trouble getting to sleep was also an intense withdrawal symptom (Wald χ²=42.31, P<0.0001) and caused significant associated distress (Wald χ²=47.76, P<0.0001). Scores on the Severity of Dependence Scale predicted cannabis withdrawal. CONCLUSIONS The Cannabis Withdrawal Scale can be used as a diagnostic instrument in clinical and research settings where regular monitoring of withdrawal symptoms is required.

Quantifying the Clinical Significance of Cannabis Withdrawal

Background and Aims Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt. Methods and Results A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p = 0.0001). Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p = 0.03). Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p = 0.001). Conclusions Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes.

Nabiximols as an Agonist Replacement Therapy During Cannabis Withdrawal: A Randomized Clinical Trial

IMPORTANCE There are no medications approved for treating cannabis dependence or withdrawal. The cannabis extract nabiximols (Sativex), developed as a multiple sclerosis treatment, offers a potential agonist medication for cannabis withdrawal. OBJECTIVE To evaluate the safety and efficacy of nabiximols in treating cannabis withdrawal. DESIGN, SETTING, AND PARTICIPANTS A 2-site, double-blind randomized clinical inpatient trial with a 28-day follow-up was conducted in New South Wales, Australia. Participants included 51 DSM-IV-TR cannabis-dependent treatment seekers. INTERVENTIONS A 6-day regimen of nabiximols (maximum daily dose, 86.4 mg of Δ9-tetrahydrocannabinol and 80 mg of cannabidiol) or placebo with standardized psychosocial interventions during a 9-day admission. MAIN OUTCOMES AND MEASURES Severity of cannabis withdrawal and cravings (Cannabis Withdrawal Scale), retention in withdrawal treatment, and adverse events. Secondary outcomes include postwithdrawal cannabis use, health outcomes, and psychosocial outcomes. RESULTS Nabiximols treatment significantly reduced the overall severity of cannabis withdrawal relative to placebo (F8,377.97 = 2.39; P = .01), including effects on withdrawal-related irritability, depression, and cannabis cravings. Nabiximols had a more limited, but still positive, therapeutic benefit on sleep disturbance, anxiety, appetite loss, physical symptoms, and restlessness. Nabiximols patients remained in treatment longer during medication use (unadjusted hazard ratio, 3.66 [95% CI, 1.18-11.37]; P = .02), with 2.84 the number needed to treat to achieve successful retention in treatment. Participants could not reliably differentiate between nabiximols and placebo treatment (χ21 = 0.79; P = .67), and those receiving nabiximols did not report greater intoxication (F1,6 = 0.22; P = .97). The number (F1,50 = 0.3; P = .59) and severity (F1,50 = 2.69; P = .10) of adverse events did not differ significantly between groups. Both groups showed reduced cannabis use at follow-up, with no advantage of nabiximols over placebo for self-reported cannabis use (F1,48 = 0.29; P = .75), cannabis-related problems (F1,49 = 2.33; P = .14), or cannabis dependence (F1,50 < 0.01; P = .89). CONCLUSIONS AND RELEVANCE In a treatment-seeking cohort, nabiximols attenuated cannabis withdrawal symptoms and improved patient retention in treatment. However, placebo was as effective as nabiximols in promoting long-term reductions in cannabis use following medication cessation. The data support further evaluation of nabiximols for management of cannabis dependence and withdrawal in treatment-seeking populations. TRIAL REGISTRATION anzctr.org.au Identifier: ACTRN12611000398909.

Constant relative age and size at sex change for sequentially hermaphroditic fish.

A general problem in evolutionary biology is that quantitative tests of theory usually require a detailed knowledge of the underlying trade‐offs, which can be very hard to measure. Consequently, tests of theory are often constrained to be qualitative and not quantitative. A solution to this problem can arise when life histories are viewed in a dimensionless way. Recently, dimensionless theory has been developed to predict the size and age at which individuals should change sex. This theory predicts that the size at sex change/maximum size (L50/Lmax), and the age at sex change/age at first breeding (τ/α) should both be invariant. We found support for these two predictions across 52 species of fish. Fish change sex when they are 80% of their maximum body size, and 2.5 times their age at maturity. This invariant result holds despite a 60 and 25 fold difference across species in maximum size and age at sex change. These results suggest that, despite ignoring many biological complexities, relatively simple evolutionary theory is able to explain quantitatively at what point sex change occurs across fish species. Furthermore, our results suggest some very broad generalities in how male fitness varies with size and age across fish species with different mating systems.

SEX-RATIO EVOLUTION IN SEX CHANGING ANIMALS

Abstract Sex allocation theory is often able to make clear predictions about when individuals should facultatively adjust their offspring sex ratio (proportion male) in response to local conditions, but not the consequences for the overall population sex ratio. A notable exception to this is in sex changing organisms, where theory predicts that: (1) organisms should have a sex ratio biased toward the “first” sex; (2) the bias should be less extreme in partially sex changing organisms, where a proportion of the “second” sex matures directly from the juvenile stage; and (3) the sex ratio should be more biased in protogynous (female first) than in protandrous (male first) species. We tested these predictions with a comparative study using data from 121 sex changing animal species spanning five phyla, covering fish, arthropods, echinoderms, molluscs, and annelid worms. We found support for the first and third predictions across all species. The second prediction was supported within the protogynous species (mainly fish), but not the protandrous species (mainly invertebrates).

Life history: changing sex at the same relative body size.

Sex change occurs in a variety of animals, including fish, echinoderms, crustaceans, molluscs and polychaete worms. Here we show that the relative timing of sex change is surprisingly invariant across all animals: 91–97% of the variation in size at sex change across species can be explained by the simple rule that individuals change sex when they reach 72% of their maximum size. This suggests that there is a fundamental similarity across all animals, from a 2-mm-long crustacean to a 1.5-m-long fish (Fig. 1), in the underlying forces that select for sex change.

Characteristics of Iranian Women Seeking Drug Treatment

BACKGROUND In the west, men are twice as likely as women to develop a drug problem, but female users have higher rates of morbidity than male users. Iran has the world highest per capita opiate consumption, but little is known about female drug users. In 2007, we established a free methadone clinic with ancillary services for female drug users in South Tehran. The aim was to explore the characteristics of female drug users seeking treatment for heroin dependence in Iran. Clients were interviewed about demographic characteristics, drug use and treatment history, and drug-related health problems. Urine and blood samples were collected and tested for morphine, HIV, hepatitis C virus (HCV), and sexually transmitted infections (STIs). METHODS Between August 2007 and October 2008, 78 women completed a baseline interview. The median age was 37 years, the main ethnic background was Persian (65%), and half of the clients were married. Opium and heroin and opium use was reported by 69% (n=54) and 87% (n=68) of clients, respectively. The mean duration of heroin use problems was 10.5 years, and only 20% of women reported ever having received drug treatment. HIV and HCV seroprevalence was 5% and 24%, respectively. Forty percent were sexually active when interviewed, and one third tested positive for an STI. Women had poor social functioning, high levels of depression, and poor general health. RESULTS AND CONCLUSIONS Our clients were dependent users with a multitude of problems who had little or no contact with treatment agencies before this study. Many clients had made a transition from using opium to using heroin, and some had commenced injecting, placing them at risk for HIV and HCV infection. More women-only drug treatment services are needed to facilitate womens entry into drug treatment.

A Dimensionless Invariant for Relative Size at Sex Change in Animals: Explanation and Implications

Recent comparative studies across sex‐changing animals have found that the relative size and age at sex change are strikingly invariant. In particular, 91%–97% of the variation in size at sex change across species can be explained by the simple rule that individuals change sex when they reach 72% of their maximum body size. However, this degree of invariance is surprising and has proved controversial. In particular, it is not clear why this result should hold, given that there is considerable biological variation across species in factors that can influence the evolutionarily stable timing of sex change. Our overall aim here is to explain this result and determine the implications for other life‐history variables. Specifically, we use a combination of approaches to formalize and make explicit previous analytical theory in this area, examine the robustness of the empirical invariance result, and carry out sensitivity analyses to determine what the empirical data imply about the mean value and variation in several key life‐history variables.

Changes in cigarette and alcohol use during cannabis abstinence

OBJECTIVE Cannabis causes lower mortality and morbidity than alcohol and tobacco so it is clinically important if quitting cannabis is associated with substitution with these substances. This study tests if cannabis is substituted with alcohol and/or tobacco during cannabis abstinence, and factors predicting such substitution. METHOD A secondary analysis of a prospective community based study quantified cannabis, alcohol and tobacco use with Timeline Follow-back during a two-week voluntary cannabis abstinence and at one-month follow-up in non-treatment seeking cannabis users (n=45). Cannabis use was verified by urine THC-COOH levels. RESULTS Alcohol use increased by 8 standard units (SU; d=0.48)/week and cigarette use by 14 cigarettes/week (d=0.29) during cannabis abstinence. Those using less of each substance at baseline had greater increases during cannabis abstinence (alcohol P<0.0001, tobacco P=0.01). There was a decrease in alcohol (-4.8 SU, d=-0.29) and tobacco (-13 cigarettes/week, d=-0.26) use at follow-up, when most participants (87%, n=39) had resumed cannabis use. Increased cigarette use was predicted by cannabis withdrawal related sleep difficulty (insomnia) (P=0.05), restlessness (P=0.03) and physical symptoms (P=0.02). Neither alcohol nor cigarette use increased significantly in those (13.3%, n=6) who remained abstinent from cannabis through to follow-up. CONCLUSIONS Abstaining from cannabis was associated with increases in alcohol and tobacco use that decreased with resumption of cannabis use; however there were no increases in individuals who remained abstinent from cannabis at one-month follow-up. Tobacco use did not increase in those experiencing milder cannabis withdrawal symptoms. Research on substitution in treatment seekers during outpatient cannabis abstinence is needed.