TY  - JOUR
AU  - Baumgartner, Christian
AU  - Schaub, Michael Patrick
AU  - Wenger, Andreas
AU  - Malischnig, Doris
AU  - Augsburger, Mareike
AU  - Walter, Marc
AU  - Berger, Thomas
AU  - Stark, Lars
AU  - Ebert, David Daniel
AU  - Keough, Matthew T
AU  - Haug, Severin
PY  - 2021
DA  - 2021/4/30
TI  - CANreduce 2.0 Adherence-Focused Guidance for Internet Self-Help Among Cannabis Users: Three-Arm Randomized Controlled Trial
JO  - J Med Internet Res
SP  - e27463
VL  - 23
IS  - 4
KW  - cannabis
KW  - common mental disorders
KW  - adherence
KW  - social presence
KW  - internet
KW  - cognitive behavioral therapy
KW  - motivational interviewing
KW  - therapy
KW  - mental health
KW  - mental disorder
KW  - guidance
KW  - self-help
KW  - drug abuse
KW  - randomized controlled trial
AB  - Background: Despite increasing demand for treatment among cannabis users in many countries, most users are not in treatment. Internet-based self-help offers an alternative for those hesitant to seek face-to-face therapy, though low effectiveness and adherence issues often arise. Objective: Through adherence-focused guidance enhancement, we aimed to increase adherence to and the effectiveness of internet-based self-help among cannabis users. Methods: From July 2016 to May 2019, cannabis users (n=775; male: 406/575, 70.6%, female: 169/575, 29.4%; age: mean 28.3 years) not in treatment were recruited from the general population and were randomly assigned to (1) an adherence-focused guidance enhancement internet-based self-help intervention with social presence, (2) a similar intervention with an impersonal service team, and (3) access to internet as usual. Controls who were placed on a waiting list for the full intervention after 3 months underwent an assessment and had access to internet as usual. The primary outcome measurement was cannabis-use days over the preceding 30 days. Secondary outcomes included cannabis-dependence severity, changes in common mental disorder symptoms, and intervention adherence. Differences between the study arms in primary and secondary continuous outcome variables at baseline, posttreatment, and follow-up were tested using pooled linear models. Results: All groups exhibited reduced cannabis-use days after 3 months (social presence: –8.2 days; service team: –9.8 days; internet as usual: –4.2 days). The participants in the service team group (P=.01, d=.60) reported significantly fewer cannabis-use days than those in the internet as usual group; the reduction of cannabis use in the social presence group was not significant (P=.07, d=.40). There was no significant difference between the 2 intervention groups regarding cannabis-use reduction. The service team group also exhibited superior improvements in cannabis-use disorder, cannabis-dependence severity, and general anxiety symptoms after 3 months to those in the internet as usual group. Conclusions: The adherence-focused guidance enhancement internet-based self-help intervention with an impersonal service team significantly reduced cannabis use, cannabis-use disorder, dependence severity, and general anxiety symptoms. Trial Registration: ISRCTN Registry ISRCTN11086185; http://www.isrctn.com/ISRCTN11086185 
SN  - 1438-8871
UR  - https://www.jmir.org/2021/4/e27463
UR  - https://doi.org/10.2196/27463
UR  - http://www.ncbi.nlm.nih.gov/pubmed/33929333
DO  - 10.2196/27463
ID  - info:doi/10.2196/27463
ER  -