The efficacy of any approach for dealing with substance abuse can be investigated scientifically: try it, and compare with a control group, trying to control fo

The efficacy of any approach for dealing with substance abuse can be investigated scientifically: try it, and compare with a control group, trying to control for as many variables as you can. If it creates a significant difference, then something is probably going on. If there's no significant difference, then it probably doesn't work. Absence of evidence is, of course, evidence of absence. None of this changes when the approach in question involves hypothetical supernatural intervention.