Funding not received; study was never started

The aims of this study are: 1) to estimate the effect size of HRV biofeedback for stress in adolescents undergoing cognitive behavioral therapy (CBT) for cannabis use disorder (primary outcome: Perceived Stress Scale) and 2) to estimate the effect size of HRV biofeedback for cannabis use in adolescents undergoing CBT for cannabis use disorder (primary outcome: number of days used cannabis in the past 30 days).

Inclusion Criteria:

• be between the ages of 13 and 19 years, with a parent or legal guardian available to complete parental assessments, if the participant is a minor
• meet Diagnostic and Statistical Manual of Mental Disorders, 5th edition, (DSM-V) criteria for cannabis use disorder by clinical interview;
• be medically healthy;
• be willing to participate in the study intervention and assessments;
• plan to live locally for at least 4 months;
• be able to read English well enough to complete study questionnaires;
• have self-reported cannabis use in the past 28 days;
• have a Perceived Stress Scale score > 20.

Exclusion Criteria:

• current or past psychosis;
• bipolar I or II disorder;
• the need to take psychotropic medications at any time during the study;
• pregnancy;
• psychiatric or substance use disorder that cannot be managed with outpatient care (e.g. alcohol withdrawal, severe major depressive disorder, significant suicidal ideation); and
• medications known to affect HRV (e.g. albuterol, pseudoephedrine, beta adrenergic blockers).