Aims
COVID-19 has had a detrimental impact on mental health, and cannabis users might be particularly vulnerable. We aimed to investigate whether levels of apathy and anhedonia have changed since the onset of the pandemic, in adolescent and adult cannabis users and controls.

Methods
Cannabis users (262 adults 18-30 years, 205 adolescents 16-17 years) and controls (173 adults, 176 adolescents) completed a web-based survey, including measures of apathy (Apathy Evaluation Scale) and anhedonia (Snaith-Hamilton Pleasure Scale). Both measures were completed twice, first referring to the three-month period before lockdown measures were implemented in the UK, and second referring to the past two weeks. Scores were investigated with fully-factorial mixed model ANOVAs, with Time as the within-subjects factor, and User-Group and Age-Group as between-subjects factors.

Results
Results revealed a main effect of Time (‘p’ <.001) and a Time*User-Group interaction (‘p’ <.05) in both models, suggesting greater apathy and anhedonia scores with time, and a greater increase in controls. The between-subjects User-Group*Age-Group interaction revealed lower scores overall in adult users compared to adult controls, while the reverse was true for adolescents (‘p ‘= .058 for AES, ‘p’ = .001 for SHAPS).

Conclusion
Apathy and anhedonia levels have increased since the onset of the COVID-19 pandemic. Adolescent users have the highest levels of both apathy and anhedonia overall, and this increase is less pronounced in adult cannabis users. Current and novel psychological and pharmacological treatments aimed at reducing the negative impact of COVID-19 on motivation and mental health should be developed and implemented.

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