Effect Size in Efficacy Trials of Women With Decreased Sexual Desire.
Pyke. Robert E RE; Clayton. Anita H AH
Key Findings
- Medications such as testosterone, flibanserin, and the peptide bremelanotide produced a large effect size of about 1.0.
- Psychotherapy methods (CBT and mindfulness) also yielded a similarly large effect size of about 1.0.
- Placebo produced a moderate effect size (~0.55), whereas waitâlist control showed a negligible effect (~0.05).
- The similarity in effect sizes suggests that the specific treatment (drug vs therapy) may be less important than the fact that participants receive active care.
Practical Outcomes
- For biohackers considering pt-141, the data confirm it can be as effective as intensive psychotherapy for boosting sexual desire, but expect a noticeable placebo component. Combining pt-141 with supportive counseling may maximize benefits, while recognizing that simply receiving attention and evaluation already helps. No new dosing guidance is provided, so stick to established dosing protocols.
Summary
In studies of women with low sexual desire, both drug treatments (including the peptide bremelanotide, also called pt-141) and talkâtherapy approaches showed a very large improvement (Cohen's d ââŻ1.0). A sugarâpill placebo still helped a fair amount (dâŻââŻ0.55), while doing nothing (waitâlist) barely moved the needle (dâŻââŻ0.05).
Abstract
Regarding hypoactive sexual desire disorder (HSDD) in women, some reviewers judge the effect size small for medications vs placebo, but substantial for cognitive behavior therapy (CBT) or mindfulness meditation training (MMT) vs wait list. However, we lack comparisons of the effect sizes for the active intervention itself, for the control treatment, and for the differential between the two. For efficacy trials of HSDD in women, compare effect sizes for medications (testosterone/testosterone transdermal system, flibanserin, and bremelanotide) and placebo vs effect sizes for psychotherapy and wait-list control. We conducted a literature search for mean changes and SD on main measures of sexual desire and associated distress in trials of medications, CBT, or MMT. Effect size was used as it measures the magnitude of the intervention without confounding by sample size. Cohen d was used to determine effect sizes. For medications, mean (SD) effect size was 1.0 (0.34); for CBT and MMT, 1.0 (0.36); for placebo, 0.55 (0.16); and for wait list, 0.05 (0.26). Recommendations of psychotherapy over medication for treatment of HSDD are premature and not supported by data on effect sizes. Active participation in treatment conveys considerable non-specific benefits. Caregivers should attend to biological and psychosocial elements, and patient preference, to optimize response. Few clinical trials of psychotherapies were substantial in size or utilized adequate control paradigms. Medications and psychotherapies had similar, large effect sizes. Effect size of placebo was moderate. Effect size of wait-list control was very small, about one quarter that of placebo. Thus, a substantial non-specific therapeutic effect is associated with receiving placebo plus active care and evaluation. The difference in effect size between placebo and wait-list controls distorts the value of the subtraction of effect of the control paradigms to estimate intervention effectiveness. Pyke RE, Clayton AH. Effect Size in Efficacy Trials of Women With Decreased Sexual Desire. Sex Med Rev 2018;6:358-366.
Study Information
pubmed
2018
2018-03-22T00:00:00.000Z
10.1016/j.sxmr.2018.01.003
15
34