Our everyday behaviours, such as physical activity, sleep, diet, meditation, and social connections, have a potent impact on our mental health and the health of our brain. BrainPark is working to harness this power by developing lifestyle-based interventions for mental health and investigating how they do and don’t change the brain, and for whom they are most effective. In this webinar, Dr Rebecca Segrave and Dr Chao Suo will discuss BrainPark’s approach to developing lifestyle-based interventions to help people get better control of compulsive behaviours, and the multi-modality neuroimaging approaches they take to investigating outcomes. The webinar will explore two current BrainPark trials: 1. Conquering Compulsions - investigating the capacity of physical exercise and meditation to alter reward processing and help people get better control of a wide range of unhelpful habits, from drinking to eating to cleaning. 2. The Brain Exercise Addiction Trial (BEAT) - an NHMRC funded investigation into the capacity of physical exercise to reverse the brain harms caused by long-term heavy cannabis use. Dr Rebecca Segrave is Deputy Director and Head of Interventions Research at BrainPark, the David Winston Turner Senior Research Fellow within the Turner Institute for Brain and Mental Health, and an AHRPA registered Clinical Neuropsychologist. Dr Chao Suo is Head of Technology and Neuroimaging at BrainPark and a Research Fellow within the Turner Institute for Brain and Mental Health.

COVID-19 lockdown measures have caused severe disruptions to work and education and prevented people from engaging in many rewarding activities. Cannabis users may be especially vulnerable, having been previously shown to have higher levels of apathy and anhedonia than non-users. In this survey study, we measured apathy and anhedonia, before and after lockdown measures were implemented, in n = 256 adult and n = 200 adolescent cannabis users and n = 170 adult and n = 172 adolescent controls. Scores on the Apathy Evaluation Scale (AES) and Snaith-Hamilton Pleasure Scale (SHAPS) were investigated with mixed-measures ANCOVA, with factors user group, age group, and time, controlling for depression, anxiety, and other drug use. Adolescent cannabis users had significantly higher SHAPS scores before lockdown, indicative of greater anhedonia, compared with adolescent controls (P = .03, η p2 = .013). Contrastingly, adult users had significantly lower scores on both the SHAPS (P < .001, η p2 = .030) and AES (P < .001, η p2 = .048) after lockdown compared with adult controls. Scores on both scales increased during lockdown across groups, and this increase was significantly smaller for cannabis users (AES: P = .001, η p2 = .014; SHAPS: P = .01, η p2 = .008). Exploratory analyses revealed that dependent cannabis users had significantly higher scores overall (AES: P < .001, η p2 = .037; SHAPS: P < .001, η p2 = .029) and a larger increase in scores (AES: P = .04, η p2 =.010; SHAPS: P = .04, η p2 = .010), compared with non-dependent users. Our results suggest that adolescents and adults have differential associations between cannabis use as well as apathy and anhedonia. Within users, dependence may be associated with higher levels of apathy and anhedonia regardless of age and a greater increase in levels during the COVID-19 lockdown.

Chemotherapeutic drugs (used for treating cancer), HIV infection and antiretroviral therapy (ART) can independently cause difficult-to-manage painful neuropathy. Paclitaxel, a chemotherapeutic drug, for example is associated with high incidence of peripheral neuropathy, around 71% of the patients of which 27% of these develop neuropathic pain. Use of cannabis or phytocannabinoids has been reported to improve pain measures in patients with neuropathic pain, including painful HIV-associated sensory neuropathy and cancer pain. Phytocannabinoids and endocannabinoids, such as anandamide and 2-arachidonoylglycerol (2-AG), produce their effects via cannabinoid (CB) receptors, which are present both in the periphery and central nervous system. Endocannabinoids are synthesized in an “on demand” fashion and are degraded by various enzymes such as fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL). Various studies, including those from our group, suggest that there are changes in gene and protein expression of endocannabinoid molecules during chemotherapy-induced neuropathic pain (CINP), HIV and antiretroviral-induced neuropathic pain. Analysis of endocannabinoid molecule expression in the brain, spinal cord and paw skin using LC-MS/MS show that there is a specific deficiency of the endocannabinoids 2-AG and/or anandamide in the periphery during CINP. Various drugs including endocannabinoids, cannabidiol, inhibitors of FAAH and MGL, CB receptor agonists, desipramine and coadministered indomethacin plus minocycline have been found to either prevent the development and/or attenuate established CINP, HIV and antiretroviral-induced neuropathic pain in a CB receptor-dependent manner. The results available suggest that targeting the endocannabinoid system for prevention and treatment of CINP, HIV-associated neuropathic pain and antiretroviral-induced neuropathic pain is a plausible therapeutic option.