Clinicians' attitudes to evolutionary and genetic explanations for anxiety: a cluster-randomised study of stigmatisation

Background: Explanatory frameworks for mental disorders have an important effect on stigmatisation and clinical attitudes, with mechanistic biological explanations often yielding mixed or negative effects on prognostic optimism and empathy. Evolutionary framings may offer functional, non-pathologizing explanations which could reduce stigma and empower patients, but few attempts have been made to test this empirically. Aims: This study aimed to experimentally test whether a brief educational intervention based on an evolutionary explanation of anxiety, compared to a genetic explanation, would influence clinicians’ attitudes in directions consistent with anti-stigma goals. Method: In a pre-registered, multi-site, double-blind experiment, 171 practicing mental health clinicians across the UK and Ireland were cluster-randomised by session to receive a 30-minute educational presentation on either evolutionary or genetic explanations for anxiety. Pre- and post-session questionnaires assessed clinicians’ optimism regarding patient recovery, the efficacy of psychosocial interventions, expected patient willingness to share diagnoses and engage in help-seeking behavior, and the perceived usefulness of the information. Data were analysed using Bayesian cumulative ordinal regression and linear regression. Results: Compared to the genetic explanation, clinicians rated the evolutionary explanation as substantially more useful for patients (Odds Ratio [OR] = 5.05, 95% Credible Interval [CI] [2.46, 10.28]) and for clinicians (OR = 3.10, 95% CI [1.62, 5.81]). These showed very large mean effect sizes, of 1.07 SD (95% CI [0.65, 1.50]) and 0.76 SD CI (95% CI [0.38, 1.17]). In comparison to the genetic explanation, the evolutionary explanation was also anticipated to increase public willingness to seek psychiatric help (OR = 1.79, 95% CI [0.93, 3.35]) and share a diagnosis (OR = 1.62, 95% CI [0.88, 2.97]). It also increased optimism about patient recovery (OR = 1.58, 95% CI [0.71, 3.46]), and the perceived effectiveness of psychosocial interventions (OR = 1.62, 95% CI [0.84, 3.10]). Furthermore, it increased clinicians’ belief in the functional usefulness of negative emotions (β = 0.25 SD, 95% CI [0.49, 0.01]). Conclusions: Distinct explanatory frameworks may be a potent determinant of clinicians' and patients’ attitudes. This study provides robust evidence that framing anxiety through an evolutionary lens can be a powerful tool to foster more optimistic and destigmatized perspectives, compared to a genetic explanation. In particular, clinicians overwhelmingly rated evolutionary explanations of anxiety as highly useful in comparison to genetic explanations. Integrating evolutionary explanations into mainstream clinical education presents an under-explored opportunity with numerous potential benefits.