Emotional blunting cured by reading original research

“Antidepressants can cause β€˜emotional blunting’, study shows”, said the Grauniad today. The study by Langley et al. (2023) randomised 66 healthy participants (i.e., not requiring antidepressants) to either SSRI (20 mg of escitalopram – a high dose) or placebo, daily for 21 days.

I have two brief observations:

Almost all the statistical analyses were classical, with 95% confidence intervals including zero interpreted as not statistically significant. The authors’ headline-grabbing finding, concerning reinforcement sensitivity, was for one of four outcomes modelled using hierarchical Bayesian modelling. A 90% highest density interval excluded zero. However, the 95% interval included zero, so following the conventions of the rest of the paper would be counted as a null effect. There was no comment on this in the paper, which strikes me as a little odd, particularly given the large number of preregistered study outcome measures (16 primary, 44 secondary, 32 other) and consequent risk of a false positive.

Additionally, the headlines and study’s conclusion claim that their findings may explain the emotional blunting sometimes reported by users of SSRIs. But I don’t see how emotional blunting relates to the probabilistic reversal learning task the authors used.

I hope the study receives critical scrutiny in the press.


Langley, C., Armand, S., Luo, Q.Β et al.Β Chronic escitalopram in healthy volunteers has specific effects on reinforcement sensitivity: a double-blind, placebo-controlled semi-randomised study.Β Neuropsychopharmacol. (2023).