Rebecca King

The effects of cannabis and alcohol on simulated driving: Influences of dose and experience.

BACKGROUND Cannabis and alcohol are the most popular drugs amongst recreational users, and most prevalent in injured and deceased drivers. Clarification of the interactive effects of these drugs upon driving behaviour is critical for reducing drug-related road deaths. OBJECTIVES The current study had two objectives, to examine the effects of cannabis and alcohol on driving performance, and identify if any differences between the effects of cannabis and alcohol on driving performance exist between regular cannabis users and non-regular cannabis users. METHODS The project involved 80 participants (49 male, 31 female) who were abstinent recreational users of alcohol and marijuana. They participated in six experimental sessions that involved the consumption of cannabis cigarettes containing no THC, 1.8% THC or 3% THC together with the consumption of alcohol to obtain either 0% BAC, 0.03% BAC or 0.05% BAC. The six sessions were double-blind, counter-balanced, placebo-controlled and medically supervised. Forty participants were allocated to the cannabis with low alcohol (0.03% BAC) group, and 40 participants were allocated to the cannabis with high alcohol (0.05% BAC) group. Driving simulator performance was assessed at 20min post-drug administration and blood samples were taken before and after driving. RESULTS Driving simulator performance was more impaired in the THC and alcohol combined conditions. Consistent with past research, the level of THC detected in blood is higher when THC is consumed with alcohol, than when cannabis is consumed alone, and regular cannabis users returned higher levels of THC in plasma than non-regular users. Generally, regular cannabis users displayed more driving errors than non-regular cannabis users.

A randomized controlled trial investigating the effect of Pycnogenol and Bacopa CDRI08 herbal medicines on cognitive, cardiovascular, and biochemical functioning in cognitively healthy elderly people: the Australian Research Council Longevity Intervention (ARCLI) study protocol (ANZCTR12611000487910)

BackgroundOne of the major challenges associated with our ageing population is the increasing incidence of age-associated cognitive decline, which has significant implications for an individuals ability to lead a productive and fulfilling life. In pure economic terms the costs of ageing reflects decreased productivity and engagement with the workforce. The maintenance of brain health underpinning intact cognition is a key factor to maintaining a positive, engaged, and productive lifestyle. In light of this, the role of diet, including supplementation with nutritional and even pharmacological interventions capable of ameliorating the neurocognitive changes that occur with age constitute vital areas of research.MethodsIn order to reduce cognitive ageing, the ARC longevity intervention (ARCLI) was developed to examine the effects of two promising natural pharmacologically active supplements on cognitive performance. ARCLI is a randomized, placebo-controlled, double-blind, 3-arm clinical trial in which 465 participants will be randomized to receive an extract of Bacopa monnieri (CDRI08 300 mg/day), Pycnogenol (150 mg/day), or placebo daily for 12 months. Participants will be tested at baseline and then at 3, 6 and 12 months post-randomization on a wide battery of cognitive, neuropsychological and mood measures, cardiovascular (brachial and aortic systolic and diastolic blood pressures as well as arterial stiffness), biochemical (assays to measure inflammation, oxidative stress and safety) as well as genetic assessments (telomere length and several Single Nucleotide Polymorphisms). The primary aim is to investigate the effects of these supplements on cognitive performance. The secondary aims are to explore the time-course of cognitive enhancement as well as potential cardiovascular and biochemical mechanisms underpinning cognitive enhancement over the 12 months of administration.ARCLI will represent one of the largest and most comprehensive experimental clinical trials in which supplements are administered to elderly participants. Results from ARCLI may help develop novel preventative health practices and nutritional/pharmacological targets in the elderly for cognitive and brain health.Trial registrationAustralia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12611000487910

The acute effects of 3,4-methylenedioxymethamphetamine and methamphetamine on driving: A simulator study

OBJECTIVES Illicit drugs such as MDMA and methamphetamine are commonly abused drugs that have also been observed to be prevalent in drivers injured in road accidents. Their exact effect on driving and driving behavior has yet to be thoroughly investigated. METHODS Sixty-one abstinent recreational users of illicit drugs comprised the participant sample, with 33 females and 28 males, mean age 25.45 years. The three testing sessions involved oral consumption of 100 mg MDMA, 0.42 mg/kg methamphetamine, or a matching placebo. The drug administration was counter-balanced, double-blind, and medically supervised. At each session driving performance was assessed 3 h and 24 h post drug administration on a computerized driving simulator. RESULTS At peak concentration overall impairment scores for driving (F(2,118)=9.042, p<0.001) and signaling (F(2,118)=4.060, p=0.020) were significantly different for the daytime simulations. Performance in the MDMA condition was worse than both the methamphetamine (p=0.023) and placebo (p<0.001) conditions and the methamphetamine condition was also observed to be worse in comparison to the placebo (p=0.055). For signaling adherence, poorer signaling adherence occurred in both the methamphetamine (p=0.006) and MDMA (p=0.017) conditions in comparison to placebo in the daytime simulations. CONCLUSIONS The findings of this study have for the first time illustrated how both MDMA and methamphetamine effect driving performance, and provide support for legislation regarding testing for the presence of illicit drugs in impaired or injured drivers as deterrents for driving under the influence of illicit drugs.

Examining the effect of dl-3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine on the standardized field sobriety tests

dl-3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine are commonly used illicit drugs that are thought to impair driving ability. The Standardized Field Sobriety Tests (SFSTs) are utilized widely to detect impairment associated with drugs other than alcohol in drivers, although limited evidence concerning MDMA and methamphetamine consumption on SFST performance exists. The aim of this study was to evaluate whether the SFSTs were a sensitive measure for identifying the presence of the specific isomer d-methamphetamine and MDMA. In a double-blind, within-subject, counter-balanced and placebo-controlled study, 58 healthy and abstinent recreational drugs users were administered three treatments: 100mg of MDMA, 0.42 mg/kg d-methamphetamine, and placebo. For each condition the SFSTs were administered at 4 and 25 h post treatment. d-methamphetamine was not found to significantly impair SFST performance unlike MDMA, which significantly impaired SFST performance in comparison to placebo with 22% of the sample failing the test at the 4h testing time-point. No differences were observed at the 25 h testing time-point for any of the conditions. It was concluded that the SFSTs are not efficient in identifying the presence of low level d-methamphetamine, and are significantly better at detecting the presence of MDMA at the levels assessed.

Does a Medicinal Dose of Kava Impair Driving? A Randomized, Placebo-Controlled, Double-Blind Study

Overview: Increasing concerns over the potentially impairing effects of prescriptive sedative drugs such as benzodiazepines on driving have been raised. However, other alternatives such as natural medicines may also carry similar risks with respect to driving safety. Kava (Piper methysticum) is a psychotropic plant commonly used both recreationally and medicinally in the United States, Australia, and the South Pacific to elicit a physically tranquilizing effect. To date no controlled study has tested a medicinal dose of kava versus placebo and a standard sedative drug on driving ability and driving safety. Objective: Due to the need to establish the safety of kava in operating a motor vehicle, we compared the acute effects of the plant extract versus the benzodiazepine oxazepam and placebo using a driving simulator. Methods: A driving simulator (AusEd) was used by 22 adults aged between 18 and 65 years after being randomly administered an acute medicinal dose of kava (180 mg of kavalactones), oxazepam (30 mg), or placebo one week apart in a crossover design trial. Results: No impairing effects on driving outcomes were found after kava administration compared to placebo. Results on specific driving outcome domains revealed that the oxazepam condition had significantly slower braking reaction time compared to the placebo condition (p =.002) and the kava condition (p =.003). The kava condition had significantly fewer lapses of concentration compared to the oxazepam condition (p =.033). No significant differences were found between conditions for steering deviation, speed deviation, and number of crashes. Results were not modified by driving experience. On the Bond-Lader visual analogue sub-scale of alertness, a significant Treatment × Time interaction (p =.032) was found, with a significant reduction over time for oxazepam decreasing alertness (p <.001), whereas no significant reduction was found in the kava or placebo conditions. Conclusion: The results indicate that a medicinal dose of kava containing 180 mg of kavalactones does not impair driving ability, whereas 30 mg of oxazepam shows some impairment. Research assessing larger recreational doses of kava on driving ability should now be conducted.

The Cognitive Ageing, Nutrition and Neurogenesis trial: Design and progress

The Cognitive Ageing, Nutrition and Neurogenesis trial hypothesizes that a combined intervention with long‐chain n‐3 polyunsaturated fatty acids (n‐3) and cocoa flavan‐3‐ols (FLAV) will mitigate the cognitive decline anticipated to naturally occur over 1 year in older adults.