Anhedonia, apathy, pleasure, and effort-based decision-making in adult and adolescent cannabis users and controls

BACKGROUND: Cannabis use may be linked with anhedonia and apathy. However, previous studies have shown mixed results and few have examined the association between cannabis use and specific reward sub-processes. Adolescents may be more vulnerable to harmful effects of cannabis than adults. This study investigated (1) the association between non-acute cannabis use and apathy, anhedonia, pleasure, and effort-based decision-making for reward, and (2) whether these relationships were moderated by age-group. METHODS: We used data from the 'CannTeen' study. Participants were 274 adult (26-29 years) and adolescent (16-17 years) cannabis users (1-7 days/week use in the past three months), and gender- and age-matched controls. Anhedonia was measured with the Snaith-Hamilton Pleasure Scale (n=274), and apathy was measured with the Apathy Evaluation Scale (n=215). Effort-based decision-making for reward was measured with the Physical Effort task (n=139), and subjective wanting and liking of rewards was measured with the novel Real Reward Pleasure task (n=137). RESULTS: Controls had higher levels of anhedonia than cannabis users (F1,258=5.35, p=.02, ηp2=.02). There were no other significant effects of User-Group and no significant User-Group*Age-Group interactions. Null findings were supported by post hoc Bayesian analyses. CONCLUSION: Our results suggest that cannabis use at a frequency of three to four days per week is not associated with apathy, effort-based decision-making for reward, reward wanting, or reward liking in adults or adolescents. Cannabis users had lower anhedonia than controls, albeit at a small effect size. These findings are not consistent with the hypothesis that non-acute cannabis use is associated with amotivation

Loneliness as an active ingredient in preventing or alleviating youth anxiety and depression : a critical interpretative synthesis incorporating principles from rapid realist reviews

Loneliness is a relatively common problem in young people (14-24 years) and predicts the onset of depression and anxiety. Interventions to reduce loneliness thus have significant potential as active ingredients in strategies to prevent or alleviate anxiety and depression among young people. Previous reviews have focused on quantitative evidence and have not examined potential mechanisms that could be targets for intervention strategies. To build on this work, in this review we aimed to combine qualitative and quantitative evidence with stakeholder views to identify interventions that appear worth testing for their potential effectiveness in reducing loneliness, anxiety and depression in young people aged 14-24 years, and provide insights into the potential mechanisms of action. We conducted a Critical Interpretative Synthesis, a systematic review method that iteratively synthesises qualitative and quantitative evidence and is explicitly focused on building theory through a critical approach to the evidence that questions underlying assumptions. Literature searches were performed using nine databases, and eight additional databases were searched for theses and grey literature. Charity and policy websites were searched for content relevant to interventions for youth loneliness. We incorporated elements of Rapid Realistic Review approaches by consulting with young people and academic experts to feed into search strategies and the resulting conceptual framework, in which we aimed to set out which interventions appear potentially promising in terms of theoretical and empirical underpinnings and which fit with stakeholder views. We reviewed effectiveness data and quality ratings for the included randomised controlled trials only. Through synthesising 27 studies (total participants n = 105,649; range 1-102,072 in different studies) and grey literature, and iteratively consulting with stakeholders, a conceptual framework was developed. A range of Intrapersonal (e.g. therapy that changes thinking and behaviour), Interpersonal (e.g. improving social skills), and Social Strategies (e.g. enhancing social support, and providing opportunities for social contact) seem worth testing further for their potential to help young people address loneliness, thereby preventing or alleviating depression and/or anxiety. Such strategies should be co-designed with young people and personalised to fit individual needs. Plausible mechanisms of action are facilitating sustained social support, providing opportunities for young people to socialise with peers who share similar experiences, and changing thinking and behaviour, for instance through building positive attitudes to themselves and others. The most convincing evidence of effectiveness was found in support of Intrapersonal Strategies: two randomised controlled studies quality-rated as good found decreases in loneliness associated with different forms of therapy (Cognitive Behavioural Therapy or peer network counselling), although power calculations were not reported, and effect sizes were small or missing. Strategies to address loneliness and prevent or alleviate anxiety and depression need to be co-designed and personalised. Promising elements to incorporate into these strategies are social support, including from peers with similar experiences, and psychological therapy.Funding Agencies|UKRI [ES/S004440/1]</p