Debate Arises Over Ketamine Study Measurement Scales and Their Impact on Treatment Outcome Interpretation
A recent letter published in npj Mental Health Research has sparked a debate regarding the measurement scales used in ketamine studies and their influence on interpreting treatment outcomes. The letter, a 'Matters Arising' critique of a 2024 meta-analysis, argues that the choice of questionnaire significantly impacts the perceived importance of the subjective experience during ketamine sessions. The original meta-analysis concluded that subjective effects explained 5 to 10 percent of ketamine outcomes and 24 percent for psilocybin, suggesting a modest role for ketamine's experiential component. However, the critic, Ramūnas Janavičius, contends that ketamine studies predominantly used dissociation scales (CADSS) or general psychiatric symptom scales (BPRS), while psilocybin studies employed mystical experience questionnaires. His re-analysis of the same ketamine studies shows that CADSS explained only 3.3 percent of the variance in outcome, whereas BPRS explained 15 percent, and mystical experience scales u...
