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.
Public Health Significance StatementPsychological 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.