Potentially harmful therapies: A meta-scientific review of evidential value.

Alexander J. Williams, Yevgeny Botanov, Robyn E. Kilshaw, Ryan E. Wong, John Kitchener Sakaluk

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Lilienfeld (2007, Psychological treatments that cause harm. Perspectives on Psychological Science, 2, 53) identified a list of potentially harmful therapies (PHTs). Given concerns regarding the replicability of scientific findings, we conducted a meta-scientific review of Lilienfeld's PHTs to determine the evidential strength for harm. We evaluated the extent to which effects used as evidence of harm were as follows: (a) (in)correctly reported; (b) well-powered; (c) statistically significant at an inflated rate given their power; and (d) stronger compared with null effects of ineffectiveness or evidence of benefit, based on a Bayesian index of evidence. We found evidence of harm from some PHTs, though most metrics were ambiguous. To enhance provision of ethical and science-based care, a comprehensive reexamination of what constitutes evidence for claims of harm is necessary. (PsycInfo Database Record (c) 2021 APA, all rights reserved) Health Significance Statement—Psychological interventions designed to help people sometimes inadvertently harm them instead. In our examination—incorporating more than 70 reports—of treatments previously identified as potentially harmful, we found that the clinical trials often provided weak scientific evidence and are therefore difficult to interpret. However, some interventions showed stronger evidence for harm and only grief therapy showed promise of benefit; as such, the remaining treatments we examined require more compelling, reproducible, and replicable evidence of benefit to justify continued clinical use. (PsycInfo Database Record (c) 2021 APA, all rights reserved)

Original languageEnglish (US)
Pages (from-to)5-18
Number of pages14
JournalClinical Psychology: Science and Practice
Issue number1
StatePublished - 2021

All Science Journal Classification (ASJC) codes

  • Clinical Psychology


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