The contribution of childhood maltreatment to the incidence of heavy cannabis use in Iran (IRNS-CCI): A multicenter, matched-pairs, nested, case-control study.

BACKGROUND: Previous studies have shown the role of the interaction between the endocannabinoid system (ECS) and life's adversities in the formation of addiction, including alcohol abuse. OBJECTIVE: Our objective was to identify childhood maltreatment (CM) patterns with the strongest impact on the probability of heavy cannabis use (THCCOOH concentrations ≥150 ng/mL) in Iran. PARTICIPANTS AND SETTING: Using survivor sampling, 350 adult participants were selected, and they were then allocated to three categories based on an optimal algorithm: 1) Sexual abuse, 2) Physical abuse, and 3) Physical neglect. METHODS: From 1 September 2019 to 1 May 2023, we implemented a multicenter, matched-pairs, nested, case-control study based on the wave 3-wave 6 data of a longitudinal, multicenter, cohort study. The cases and controls (n = 350 men) were defined according to the severity of CM. The THC potency was evaluated with the delta-9 carboxy tetrahydrocannabinol (THC-COOH) levels in urine using gas chromatography/mass spectrometry (GC/MS). We calculated the population attributable fractions (PAFs) to identify the patterns of maltreatment associated with the highest odds of high-potency cannabis use. RESULTS: Accumulating CM, including sexual abuse, physical abuse, and physical neglect, carried more than three times the risk of heavy cannabis use (OR 3.4 95 % CI 2.9-4.1), and the combination of the three indicators of maltreatment and a high BMI (25-29.9) carried more than four times the risk of heavy cannabis use (OR 4.7 95 % CI 2.7-4.1) compared to the controls. We estimated that in the case of zero CM for each of the three indicators, over 20 % of new cases of heavy cannabis use can be prevented. CONCLUSIONS: The findings show the significance of CM as a predicator of heavy cannabis use in adulthood and in the abstinence phase.

Cannabis Exposure and Adverse Pregnancy Outcomes Related to Placental Function.

Importance: Cannabis use is increasing among reproductive-age individuals and the risks associated with cannabis exposure during pregnancy remain uncertain. Objective: To evaluate the association between maternal cannabis use and adverse pregnancy outcomes known to be related to placental function. Design, Setting, and Participants: Ancillary analysis of nulliparous individuals treated at 8 US medical centers with stored urine samples and abstracted pregnancy outcome data available. Participants in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be cohort were recruited from 2010 through 2013; the drug assays and analyses for this ancillary project were completed from June 2020 through April 2023. Exposure: Cannabis exposure was ascertained by urine immunoassay for 11-nor-9-carboxy-Δ9-tetrahydrocannabinol using frozen stored urine samples from study visits during the pregnancy gestational age windows of 6 weeks and 0 days to 13 weeks and 6 days (visit 1); 16 weeks and 0 days to 21 weeks and 6 days (visit 2); and 22 weeks and 0 days to 29 weeks and 6 days (visit 3). Positive results were confirmed with liquid chromatography tandem mass spectrometry. The timing of cannabis exposure was defined as only during the first trimester or ongoing exposure beyond the first trimester. Main Outcome and Measure: The dichotomous primary composite outcome included small-for-gestational-age birth, medically indicated preterm birth, stillbirth, or hypertensive disorders of pregnancy ascertained by medical record abstraction by trained perinatal research staff with adjudication of outcomes by site investigators. Results: Of 10 038 participants, 9257 were eligible for this analysis. Of the 610 participants (6.6%) with cannabis use, 32.4% (n = 197) had cannabis exposure only during the first trimester and 67.6% (n = 413) had ongoing exposure beyond the first trimester. Cannabis exposure was associated with the primary composite outcome (25.9% in the cannabis exposure group vs 17.4% in the no exposure group; adjusted relative risk, 1.27 [95% CI, 1.07-1.49]) in the propensity score-weighted analyses after adjustment for sociodemographic characteristics, body mass index, medical comorbidities, and active nicotine use ascertained via urine cotinine assays. In a 3-category cannabis exposure model (no exposure, exposure only during the first trimester, or ongoing exposure), cannabis use during the first trimester only was not associated with the primary composite outcome; however, ongoing cannabis use was associated with the primary composite outcome (adjusted relative risk, 1.32 [95% CI, 1.09-1.60]). Conclusions and Relevance: In this multicenter cohort, maternal cannabis use ascertained by biological sampling was associated with adverse pregnancy outcomes related to placental dysfunction.

Screening and confirmation methods for the qualitative identification of nine phytocannabinoids in urine by LC-MS/MS.

Qualitative liquid chromatography tandem mass spectrometry (LC-MS/MS) methods were developed and validated to screen and confirm the presence of nine phytocannabinoids in urine. The nine phytocannabinoids targeted in the methods included Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC, 11-nor-9-carboxy-THC, cannabidiol, 7-carboxy cannabidiol, cannabinol, cannabigerol, Δ9-tetrahydrocannabivarin (THCV), and 11-nor-9-carboxy-THCV. The methods presented use a rapid, single-step enzymatic hydrolysis followed by solid-phase extraction and LC-MS/MS analysis. Limits of detection were established at 1 µg/L for non-carboxylated analytes and 5 µg/L for carboxylated analytes. The screening and confirmation methods were validated and implemented in the analysis of authentic case samples. These methods can assist forensic, medicolegal, or medical compliance investigations as the presence of phytocannabinoids, or lack there-of, may be used to help differentiate cannabis (hemp, marijuana) use from synthetic THC (dronabinol) exposure.

Sleep time differs among people who co-use cocaine and cannabis compared to people who only use cocaine.

OBJECTIVE: People who use cocaine experience numerous sleep problems and often use cannabis to mitigate these problems. However, co-using cocaine and cannabis may result in worse sleep outcomes when compared to using cocaine only. The current study examined group differences in subjective sleep outcomes among people who use cocaine and people who co-use cocaine and cannabis. METHODS: Participants were 82 individuals with cocaine use disorder who were enrolled in a randomized clinical trial for cocaine treatment. Sleep outcomes, assessed at baseline prior to treatment, were measured with the Saint Mary's Hospital Sleep Questionnaire and included total sleep time, perceived sleep quality, difficulty falling asleep, and daytime alertness. Analysis of covariance and Kruskal-Wallis tests were used to compare sleep outcomes between participants with urine samples that tested positive for both cocaine and cannabis at baseline, those who tested positive for cocaine only, and those who tested negative for all drugs. RESULTS: Total reported sleep time was highest among those with a drug negative urine, followed by those with a cocaine positive urine and those who tested positive for cocaine and cannabis. There were no differences in perceived sleep quality, difficulty falling asleep, or daytime alertness between groups. CONCLUSIONS: People who co-use cocaine and cannabis may report reduced sleep time relative to those who only use cocaine. Co-use of cannabis may exacerbate sleep difficulties in people who use cocaine by decreasing total sleep time, although it is important to note that the groups each reported similar sleep quality. Implications for treatment and directions for future research are discussed.

Alcohol substitution during one month of cannabis abstinence among non-treatment seeking youth.

OBJECTIVE: Cannabis and alcohol use are correlated behaviors among youth. It is not known whether discontinuation of cannabis use is associated with changes in alcohol use. This study assessed alcohol use in youth before, during, and after 4 weeks of paid cannabis abstinence. METHODS: Healthy, non-treatment seeking, cannabis users (n = 160), aged 14-25 years, 84% of whom used alcohol in the last month, were enrolled for a 4-week study with a 2-4 week follow-up. Participants were randomly assigned to 4 weeks of either biochemically-verified cannabis abstinence achieved through a contingency management framework (CB-Abst) or monitoring with no abstinence requirement (CB-Mon). Participants were assessed at baseline and approximately 4, 6, 10, 17, 24, and 31 days after enrollment. A follow-up visit with no cannabis abstinence requirement for CB-Abst was conducted after 2-4 weeks. RESULTS: Sixty percent of individuals assigned to the CB-Abst condition increased in frequency and quantity of alcohol consumption during the 4-week period of incentivized cannabis abstinence. As a whole, CB-Abst increased by a mean of 0.6 drinking days and 0.2 drinks per day in the initial week of abstinence (p's < 0.006). There was no evidence for further increases in drinking frequency or quantity during the 30-day abstinence period (p's > 0.53). There was no change in drinking frequency or quantity during the 4-week monitoring or follow-up periods among CB-Mon. CONCLUSIONS: On average, 4 weeks of incentivized (i.e., paid) cannabis abstinence among non-treatment seeking youth was associated with increased frequency and amount of alcohol use in week 1 that was sustained over 4 weeks and resolved with resumption of cannabis use. However, there was notable variability in individual-level response, with 60% increasing in alcohol use and 23% actually decreasing in alcohol use during cannabis abstinence. Findings suggest that increased alcohol use during cannabis abstinence among youth merits further study to determine whether this behavior occurs among treatment seeking youth and its clinical significance.

Prevalence of illicit drug use at the end of pregnancy: a cross-sectional study at the time of birth.

BACKGROUND: Drug use during pregnancy is associated with adverse perinatal outcomes. This study was conducted to assess the prevalence of consumption of drugs of abuse in pregnant women at the end of gestation. METHODS: Cross-sectional study of all consecutive pregnant women in labor admitted to a regional hospital in Calella (Barcelona, Spain) in labor over one year (2014-2015). Women who gave written consent to take part in the study provided a urine sample on admission and completed a questionnaire with toxic-habit-related questions. RESULTS: The study population included 862 women, 721 (83.6%) of which agreed to participate. Of the 721 urine samples obtained, 719 (99.7%) were valid for analysis. The prevalence of drugs of abuse was 5.4% (N.=39). Cannabis was the most frequently detected substance. No participant tested positive for opioids. In the multivariate analysis, predictors of illicit drug use were history of more than two abortions, premature delivery, self-reporting of consumption during pregnancy, poor obstetric control during gestation, and consideration of vulnerable pregnant woman. Based on the ß coefficients of these five factors, a scoring system for discriminating positivity or negativity of drugs of abuse in urine testing was calculated (area under the ROC 0.84). CONCLUSIONS: The prevalence of consumption of drugs of abuse at the end of pregnancy was 5.4%. A simple test based on five anamnestic variables is useful to discriminate women with positive and negative results of urine testing for drugs of abuse tested in this study.

Variación en el patrón de consumo de cannabinoides sintéticos de una paciente a lo largo de 2018 / Variation in the pattern of synthetic cannabinoid use by a female patient during 2018

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Interest of adjusting urine cannabinoids to creatinine level to monitor cannabis cessation therapy in heavy smokers with psychiatric disorders.

Up to 25% of hospitalized patients in a psychiatric department exhibit troubles linked to cannabis use. Weaning patients with psychiatric disorders off drugs of abuse requires specific care to improve their clinical outcome. The present study aims to develop a predictive model of urinary excretion of creatinine-normalized cannabinoids (UCNC ) and to determine UCNC thresholds corresponding to the widely used cut-offs of 20 ng/mL and 50 ng/mL for cannabinoids. One hundred thirty-two patients with 452 urine samples were included between 2013 and 2017. Urinary cannabinoids and UCNC elimination curves were computed for each patient. Using a mono-exponential mixed effect model with 88 samples from 26 subjects exhibiting at least 3 decreasing UCNC in a row, the average calculated elimination rate constant was 0.0108 ± 0.0026 h-1 , corresponding to a mean elimination half-life of 64 ± 12 hours. The use of UCNC is of particular interest because of a high inter- and intra-individual variability of urinary creatinine concentration (from 0.06 to 3.81 mg/mL). Moreover, UCNC allows for the detection of diluted or concentrated urine specimens that may lead to false positive (FP) or false negative (FN) results. Receiver operator characteristic (ROC) curves were used to assess UCNC thresholds of 32.4 and 124.7 ng/mg that provide a strong discrimination between positive and negative samples for cannabinoids cut-offs of 20 and 50 ng/mL respectively. The developed model and the defined UCNC thresholds allowed for the accurate prediction of the time needed to reach a negative UCNC result that could be used by clinicians to optimize clinical care.

Confirmed marijuana use and lymphocyte count in black people living with HIV.

BACKGROUND: Marijuana is a commonly used recreational substance with purported analgesic and mood enhancing properties. Many people living with HIV identify marijuana as a palliative substance. However, through its main psychoactive component, tetrahydrocannabinol (THC), is known to influence the immune system. The effects of marijuana use in people with HIV are still controversial, with very scant literature in Black adults. METHODS: The current study determined the differences in the lymphocyte count, specifically the number cluster differentiation 4 and 8 (CD4+ and CD8+), among patients who urine drug tested negative for THC (n = 70) and those who tested positive for THC (n = 25). The sample included 95 Black people living with HIV, 51% female, with a mean age of 46 ± 11 years. Participants provided a urine sample for substance use testing and a trained researcher extracted clinical data from clinical charts on the day of appointment. RESULTS: After adjusting for demographic and HIV-related covariates, THC-positive patients had significantly higher CD4+ and CD8+ counts than their THC-negative counterparts. CONCLUSION: These results extend previous HIV-related immunity findings in an underrepresented group, and suggest that THC use does not reduce immune function as measured by CD count. Further research is warranted on the overall effects of THC on immune function in HIV positive patients.

Provider reasons for discontinuing long-term opioid therapy following aberrant urine drug tests differ based on the type of substance identified.

OBJECTIVE: Urine drug testing (UDT) is increasingly performed as a means of identifying aberrant behavior that may be grounds for discontinuation of long-term opioid therapy (LTOT). Little is known, however, about the ways in which positive UDT results may differentially inform decisions to discontinue LTOT based on the type of substance for which the UDT screened positive. The aim of this study was to examine the likelihood of clinician-initiated discontinuation of LTOT attributed to positive UDT results across three discrete categories of substances: (1) cannabis, (2) alcohol or illicit substances (excluding cannabis), and (3) controlled prescription medications that were not prescribed. DESIGN: This retrospective study utilized the US Department of Veterans Affairs (VA) Health Care System. Corporate Data Warehouse to assemble a sample of 600 patients with substance use disorders and matched controls who were discontinued from LTOT in 2012. Comprehensive manual medical record review identified UDT results in the year prior to discontinuation and reason(s) for discontinuation. PATIENTS, PARTICIPANTS: Patients with one or more UDTs positive for a single substance (N = 185) comprised the study sample. MAIN OUTCOME MEASURE(S): Likelihood of clinician-initiated discontinuation attributed to a positive UDT across the three categories. RESULTS: Patients with one or more UDTs positive for cannabis were more likely to be discontinued from opioid therapy as a result of the positive UDT compared to those with one or more UDTs positive for nonprescribed prescription medication (adjusted odds ratio [OR] = 18.05, 95% CI = 7.29-44.66). Similarly, patients with UDTs positive for alcohol or illicit substances were more likely to be discontinued for the positive UDTs relative to patients who tested positive for nonprescribed prescription medications (adjusted OR = 13.10, 95% CI = 4.81-35.68). No difference in UDT-related discontinuation decisions was evident between patients with UDTs positive for alcohol/illicit substances versus cannabis (adjusted OR = 1.47, 95% CI = 0.57-3.77). CONCLUSIONS: High odds of UDT-related discontinuation were found in patients who tested positive for cannabis, alcohol, or illicit substances, relative to nonprescribed prescription medications.

Cannabinoid concentrations in blood and urine after smoking cannabidiol joints.

In Switzerland, the sale of cannabis with tetrahydrocannabinol (THC) content less than 1% has recently been legalized. As a consequence, cannabis with low THC and high cannabidiol (CBD) values up to approximately 25% is legally available on the market. In this study, we investigated cannabinoid blood and urine concentrations of a naive user and of a modeled chronic user after smoking a single CBD joint. Chronic use was modeled as smoking 2 joints per day for 10 days. Joints contained 200mg of cannabis with THC concentrations of 0.94% and 0.8% and CBD concentrations of 23.5% and 17% in the naive-smoker and chronic-smoker experiment, respectively. After smoking, blood and urine samples were collected for 4 and 20h after smoking start, respectively. THC blood concentrations reached 2.7 and 4.5ng/mL in the naive and chronic user, respectively. In both cases, the blood THC concentration is significantly above the Swiss road traffic threshold of 1.5ng/mL. Consequently, the user was legally unfit to drive directly after smoking. CBD blood concentrations of 45.7 and 82.6ng/mL were reached for the naive and chronic user, respectively. During the 10-day smoking period, blood and urine samples were regularly collected. No accumulation of any cannabinoid was found in the blood during this time. Urinary 11-nor-9-carboxy-THC concentrations seemed to increase during the 10-day period, which is important in abstinence testing.

Biological correlates of self-reported new and continued abstinence in cannabis cessation treatment clinical trials.

BACKGROUND: The agreement between self-reported cannabis abstinence with urine cannabinoid concentrations in a clinical trials setting is not well characterized. We assessed the agreement between various cannabinoid cutoffs and self-reported abstinence across three clinical trials, one including contingency management for abstinence. METHODS: Three cannabis cessation clinical trials where participants reported use and provided weekly urine samples for cannabis and creatinine concentration measurements were included. Bootstrapped data were assessed for agreement between self-reported 7+ day abstinence and urine cannabinoid tests using generalized linear mixed effects models for clustered binary outcomes. One study implemented contingency management for cannabis abstinence. Four hundred and seventy-three participants with 3787 valid urine specimens were included. Urine was analyzed for 11-nor-9-carboxy-Δ9-tetrahydrocannabinol and creatinine using immunoassay methods Biological cutoffs of 50, 100, and 200 ng/ml, as well as changes in CN normalized THCCOOH (25%/50% decrease), were assessed for agreement with self-reported abstinence during the three clinical trials. RESULTS: Agreement between measured THCCOOH and self-reported abstinence increases with increasing cutoff concentrations, while the agreement with self-reported non-abstinence decreases with increasing cutoff concentrations. Combining THCCOOH cutoffs with recent changes in CN-THCCOOH provides a better agreement in those self-reporting abstinence. Participants in the studies that received CM for abstinence had a lower agreement between self-reported abstinence and returned to use than those in studies that did not have a contingency management component. CONCLUSION: Using combinations of biological measurements and self-reported abstinence, confirmation of study related abstinence may be verifiable earlier and with greater accuracy than relying on a single measurement.

Comparing the Validity of Self-Report and Urinalysis for Substance Use among Former Inmates in the Northeastern United States.

BACKGROUND: Problems with self-reported drug use include difficulties with recall and recognition as well as the desire to respond to questions in a socially desirable manner. Various methods have been developed to improve and/or validate estimates based on direct questioning of individuals regarding their substance use. For this study, we were interested in validating self-reported use of: 1) tobacco, 2) marijuana, and 3) other substances (i.e., heroin, cocaine, opiates, oxycodone, benzodiazepines, methamphetamine, phencyclidine, and barbiturates) employing urinalysis among inmates who participated in a randomized controlled trial of a smoking abstinence intervention in a tobacco-free prison located in the northeastern United States. METHODS: Two-hundred and seven men and women with a mean age of 34.9 (standard deviation = 9.0) completed questions regarding their substance use on a 7-day Timeline Follow-Back and provided urine specimens three weeks following prison release. RESULTS: Self-reported tobacco and marijuana use were highly consistent with urine drug testing in terms of overall agreement and Kappa (93.7% and.804 for tobacco, respectively; and 90.3% and.804 for marijuana, respectively); however, consistency was much lower for other drug use grouped together (62.7% and.270). DISCUSSION: Although some former inmates may not accurately report substance use, our findings indicate that they are in the minority, suggesting that self-report is valid for tobacco and marijuana use but much less so for other drugs grouped together. Future research should be conducted with a larger and more diverse sample of former inmates to establish the generalizability of our findings from this study.

Effect of tramadol addiction alone and its co-abuse with cannabis on urinary excretion of Copper, Zinc, and Calcium among Egyptian addicts.

BACKGROUND: The use of illicit drugs has become a worldwide health problem. Substances with the potential to be abused may have direct or indirect effects on physiologic mechanisms that lead to organ system dysfunction and diseases. OBJECTIVE: The present study aims to investigate the structural and reabsorption integrity of the nephron among Egyptian addicts of tramadol alone and coabused with cannabis. METHODS: Sixty-five males were included in the study, they were classified into control group (G1=19), tramadol addicts group (G2=18), and tramadol coabused with cannabis addicts group (G3=28). Parameters investigated for structural integrity were urinary levels ofleucineaminopeptidase and N-acetyl-ß-D-glucosaminidase, and urinary parameters for reabsorption integrity were levels of copper and zinc as well as calcium, also urinary creatinine was measured. In addition, urinary levels of tramadol and tetrahydrocannabinol were estimated. RESULTS: Among the two addicted groups, all measured parameters were not significantly different in comparison with the control group except for urinary calcium excretion which was found to be significantly increased among the two addicted groups. CONCLUSION: Both tramadol addiction alone or coabused with cannabis causes increased urinary excretion of calcium, indicating reabsorption dysfunction of calcium without affecting structural integrity along the nephron.

Incremental validity of estimated cannabis grams as a predictor of problems and cannabinoid biomarkers: Evidence from a clinical trial.

BACKGROUND: Quantifying cannabis use is complex due to a lack of a standardized packaging system that contains specified amounts of constituents. A laboratory procedure has been developed for estimating physical quantity of cannabis use by utilizing a surrogate substance to represent cannabis, and weighing the amount of the surrogate to determine typical use in grams. METHOD: This secondary analysis utilized data from a multi-site, randomized, controlled pharmacological trial for adult cannabis use disorder (N=300), sponsored by the National Drug Abuse Treatment Clinical Trials Network, to test the incremental validity of this procedure. In conjunction with the Timeline Followback, this physical scale-based procedure was used to determine whether average grams per cannabis administration predicted urine cannabinoid levels (11-nor-9-carboxy-Δ9-tetrahydrocannabinol) and problems due to use, after accounting for self-reported number of days used (in the past 30 days) and number of administrations per day in a 12-week clinical trial for cannabis use disorder. RESULTS: Likelihood ratio tests suggest that model fit was significantly improved when grams per administration and relevant interactions were included in the model predicting urine cannabinoid level (X2=98.3; p<0.05) and in the model predicting problems due to cannabis use (X2=6.4; p<0.05), relative to a model that contained only simpler measures of quantity and frequency. CONCLUSIONS: This study provides support for the use of a scale-based method for quantifying cannabis use in grams. This methodology may be useful when precise quantification is necessary (e.g., measuring reduction in use in a clinical trial).

A method to achieve extended cannabis abstinence in cannabis dependent patients with schizophrenia and non-psychiatric controls.

BACKGROUND: Cannabis use disorders (CUD) are common in schizophrenia (~25%) compared to the general population (~3%). Tetrahydrocannabinol (THC), the principal psychoactive component in cannabis is fat-soluble, resulting in an extended period for cannabinoid elimination. While detection of cannabinoids in urine is indicative of prior cannabis exposure, time of last use is difficult to verify sustained abstinence for extended periods (e.g., 28-days) in chronic cannabis users. Therefore, we evaluated the utility of a sustained cannabis abstinence paradigm in patients with schizophrenia and non-psychiatric controls. METHODS: Cannabis dependent patients (n=19) and controls (n=20) underwent 28-days of monitored cannabis abstinence facilitated with contingency management. Urine samples were taken twice weekly. Abstinence was evaluated using 1) Self-report; 2) Qualitative biochemical confirmation using MEDTOX; and 3) in a subset of participants (schizophrenia, n=13; controls, n=13) gas chromatography-mass spectrometry (GC-MS) was performed to obtain quantitative creatinine-normalized carboxy-THC (THC-COOH) metabolite levels <20ng/mL). Subjective assessments were used to assess behavioral correlates of cannabis abstinence and further supported time-dependent abstinence trajectories. RESULTS: Abstinence rates of 42.1% (8/19) in patients and 55% (11/19) in controls (p=0.53) were observed. Increased cannabis withdrawal symptoms in both patients and controls supported abstinence. DISCUSSION: Our results suggest a feasible method for identification of short-term cannabis abstinence in individuals with schizophrenia at rates comparable to controls. Monitoring sustained abstinence may have implications for potential interventions for CUDs in schizophrenia.

Risk factors for non-fatal occupational injuries among construction workers: A case-control study.

BACKGROUND: Substance abuse is a serious problem, because it affects both workers and young people. Prevalence and consequences of cannabis abuse among construction workers in particular are not well studied in Egypt. OBJECTIVES: To determine the association between non-fatal occupational injuries among construction workers and their demographic and occupational factors and to assess the frequency of cannabis abuse and its relationship to injury severity and workdays lost. SUBJECTS AND METHODS: A case-control study was conducted at Mansoura Emergency Hospital. Cases were 100 acutely injured male workers. A control group of 90 healthy age-matched workers was selected from 8 construction sites. Workers were interviewed, and a questionnaire was completed that included socio-demographic data, full occupational history, and causes and type of injury. Injury outcome measures included lost workdays and the injury severity score (ISS). Cannabis abuse in injured workers was monitored by preliminary testing of urine and confirmatory testing of blood. RESULTS: Logistic regression analysis revealed that the independent predictors of occupational injuries were rural residence, being a carpenter or painter and past history of injuries. The most common accidents were slipping falls (62%). Confirmed cannabis test was positive in 51.1% of the injured workers. Median days away from work were greater among cannabis users than non-users. The ISS was significantly higher among users compared to non-users ( p < 0.05). CONCLUSION: Cannabis abuse can increase injury severity and prolong workdays lost. Drug testing is recommended for at-risk construction workers with inadequate safety measures.

Effects of extended cannabis abstinence on clinical symptoms in cannabis dependent schizophrenia patients versus non-psychiatric controls.

BACKGROUND: Rates of cannabis use among patients with schizophrenia are high, however little is understood about clinical effects of continued cannabis use and cessation after illness onset. Therefore, we investigated the effects of 28-days of cannabis abstinence on psychotic and depressive symptomatology in cannabis dependent patients with schizophrenia. METHOD: Males with cannabis dependence and co-morbid schizophrenia (n=19) and non-psychiatric controls (n=20) underwent 28-days of monitored cannabis abstinence. Clinical symptoms were assessed at baseline and then weekly. Abstinence was encouraged using weekly therapy sessions and contingency reinforcement, confirmed by twice-weekly urine assays. RESULTS: Forty-two percent (8/19) of patients and 55% (11/20) of controls achieved 28-days of sustained cannabis abstinence. In patients, PANSS subscores did not change over time irrespective of abstinence status. In contrast, patient abstainers demonstrated a more pronounced reduction in depression scores compared to non-abstainers, however, the Abstinence Status x Time interaction was non-significant. DISCUSSION: Short-term (28-days) cannabis abstinence is not associated with improvement in psychotic symptoms, but may be associated with improvement in depressive symptomatology in patients with schizophrenia. Future studies employing larger samples as well as a continuous cannabis-using group may help to better characterize the causal effects of cannabis on symptom outcomes in this disorder.