CapOpus is the name of a randomized controlled trial (RCT) running in Denmark at Psychiatric Center Bispebjerg (part of Region Hovedstadens Psykiatri) and physically located at Bispebjerg Hospital in Copenhagen. It is an intervention aimed at reducing cannabis consumption in young persons with comorbid severe mental illness such as schizophrenia or schizotypal personality disorder, and cannabis dependency. It is run by psychiatrist Merete Nordentoft. The presence of mental illness and cannabis dependency, abuse, or harmful use is established using the SCAN interview's chapters 11 and 12.