Levels of Evidence:
|SOURCE OF EVIDENCE
|Evidence obtained from meta-analysisG or systematic reviews of randomized controlled trialsG, and/or synthesis of multiple studies primarily of quantitative research.
|Evidence obtained from at least one randomized controlled trial.
|Evidence obtained from at least one well-designed controlled study without randomization.
|Evidence obtained from at least one other type of well-designed quasi-experimental study, without randomization.
|Synthesis of multiple studies primarily of qualitative research.
|Evidence obtained from well-designed non-experimental observational studies, such as analytical studiesG or descriptive studies, and/or qualitative studies.
|Evidence obtained from expert opinion or committee reports, and/or clinical experiences of respected authorities.
Addiction and Mental Health