Evaluating the efficacy of a web-based self-help intervention with and without chat counseling in reducing the cocaine use of problematic cocaine users: the study protocol of a pragmatic three-arm randomized controlled trial

Table 2 Inclusion/exclusion criteria and reasoning

Inclusion criteria	Reasoning
Minimum age of 18 years	To ensure a minimum age for participation
Cocaine use > 3 occasions in the past 30 days	To also include occasional users to provide extended study validity
Exclusion Criteria	Reasoning
Participation in other psycho-social or pharmacological treatments for the reduction/cessation of cocaine use	To avoid confounding treatment effects
Opioid use during the past 30 days (exception: substitution maintenance treatment for opioid dependence without heroin use in the past 30 days)	To avoid confounding drug effects
Previous treatment for cardiovascular problems or apoplexy	To avoid that subjects who have these health problems