RationaleAnecdotally, both acute and chronic cannabis use have been associated with apathy, amotivation, and other reward processing deficits. To date, empirical support for these effects is limited, and no previous studies have assessed both acute effects of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), as well as associations with cannabis dependence.ObjectivesThe objectives of this study were (1) to examine acute effects of cannabis with CBD (Cann + CBD) and without CBD (Cann-CBD) on effort-related decision-making and (2) to examine associations between cannabis dependence, effort-related decision-making and reward learning.MethodsIn study 1, 17 participants each received three acute vaporized treatments, namely Cann-CBD (8 mg THC), Cann + CBD (8 mg THC + 10 mg CBD) and matched placebo, followed by a 50 % dose top-up 1.5 h later, and completed the Effort Expenditure for Rewards Task (EEfRT). In study 2, 20 cannabis-dependent participants were compared with 20 non-dependent, drug-using control participants on the EEfRT and the Probabilistic Reward Task (PRT) in a non-intoxicated state.ResultsCann-CBD reduced the likelihood of high-effort choices relative to placebo (p = 0.042) and increased sensitivity to expected value compared to both placebo (p = 0.014) and Cann + CBD (p = 0.006). The cannabis-dependent and control groups did not differ on the EEfRT. However, the cannabis-dependent group exhibited a weaker response bias than the control group on the PRT (p = 0.007).ConclusionsCannabis acutely induced a transient amotivational state and CBD influenced the effects of THC on expected value. In contrast, cannabis dependence was associated with preserved motivation alongside impaired reward learning, although confounding factors, including depression, cannot be disregarded. This is the first well powered, fully controlled study to objectively demonstrate the acute amotivational effects of THC.Electronic supplementary materialThe online version of this article (doi:10.1007/s00213-016-4383-x) contains supplementary material, which is available to authorized users.
The purpose of this study was to determine the effects of a 12-week standing program on ankle mobility and femur bone mineral density in patients with lower limb paralysis following recent spinal cord injury. An assessor-blinded within-subject randomised controlled trial was undertaken. Twenty patients with lower limb paralysis following a recent spinal cord injury were recruited. Subjects stood weight-bearing through one leg on a tilt-table for 30 minutes, three times each week for 12 weeks. By standing on one leg a large dorsiflexion stretch was applied to the ankle and an axial load was applied to the bones of the weight-bearing leg. Ankle mobility and femur bone mineral density of both legs were measured at the beginning and end of the study. Ankle mobility (range of motion) was measured with the application of a 17 Nm dorsiflexion torque. Femur bone mineral density was measured using dual energy X-ray absorptiometry (DEXA). The effect of standing was estimated from the difference between legs in mean change of ankle mobility and femur bone mineral density. The results indicated a mean treatment effect on ankle mobility of 4 degrees (95% CI 2 to 6 degrees) and on femur bone mineral density of 0.005 g/cm(2) (95% CI -0.015 to 0.025 g/cm(2)). Tilt-table standing for 30 minutes, three times per week for 12 weeks has a small effect on ankle mobility, and little or no effect on femur bone mineral density. It is unclear whether clinicians and patients would consider such effects to be clinically worthwhile.
The results of four 'moderate' quality studies show a convincing effect of stretching in people without functionally significant contracture. These findings require verification with high-quality studies. Lasting effects of intensive stretching programmes (for example, stretching applied for more than six weeks or for more than 20 minutes a day) or of stretching on people with functionally significant contracture have not yet been investigated with randomized studies.
CPM does not have clinically important effects on active knee flexion ROM, pain, function or quality of life to justify its routine use. It may reduce the risk of manipulation under anaesthesia and risk of developing adverse events although the quality of evidence supporting these findings are very low and low, respectively. The effects of CPM on other outcomes are unclear.
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