Researchers may also be interested in consulting the State of Oregon's Department of Human Services Addictions and Mental Health Services unit who publish a webpage of approved evidence-based practices and process in compliance with SB 267
Search the database most appropriate for your topic for systematic reviews or meta-analyses. If none are found, move to the most appropriate disciplinary database.
Focus on finding original research studies as opposed to literature reviews.
If you are still not finding useful articles, consider that your search may be too narrow. Sometimes you need to find items that are similar enough to your question that you can extrapolate the findings.