Feeling more, not less: the effect of psilocybin versus selective serotonin reuptake inhibitors on emotional blunting

Emotional blunting, commonly defined as a reduction in negative as well as positive emotional responsiveness, represents a clinically relevant adverse effect in antidepressant treatment. Patients describe diminished caring, empathy, enjoyment, and a sense that emotions are experienced cognitively rather than felt. This occurs in approximately half of patients with major depressive disorder (MDD) treated with selective serotonin reuptake inhibitors (SSRIs) and ranks among the most common reasons for treatment dissatisfaction and discontinuation. However, emotional blunting also overlaps with residual depressive symptoms, complicating the interpretation of whether it represents a drug-induced side effect, incomplete recovery, or both. This has motivated interest in alternative antidepressant treatments such as psilocybin, which is associated with increased emotional responsivity. This review examined whether psilocybin is superior to SSRIs regarding emotional blunting and which neurobiological and psychometric factors may underlie potential differences in emotional processing. We conducted a narrative review of randomised controlled trials, clinical studies, neuroimaging work, and mechanistic papers assessing emotional blunting, emotional processing, and related affective outcomes under SSRIs, psilocybin, and, where relevant, ketamine. Particular attention was given to head-to-head psilocybin–escitalopram studies, amygdala and network-level mechanisms, and the instruments used to operationalise emotional blunting.

The strongest comparative evidence comes from a 6-week double-blind trial in MDD, in which emotional detachment and reduced emotional responsiveness were reported more frequently under the SSRI escitalopram than under psilocybin, despite comparable antidepressant effects in both arms. Converging neuroimaging findings from the same clinical cohort suggest that escitalopram reduces neural responsiveness to emotional stimuli, including amygdala reactivity to fearful faces, and that these reductions track subjective blunting. Psilocybin did not show the same dampening effect and may preserve, or even slightly increase, responsivity to emotional stimuli. The mechanism may involve SSRIs initially reducing negative affective bias in therapeutically beneficial ways, but over time, broader reductions in emotional responsiveness may lead to blunting in some patients. Psilocybin, through acute 5-HT2A-mediated changes in emotional processing, amygdala responsivity, default-mode-network dynamics, and neuroplasticity, may instead facilitate emotional access or breakthrough. The evidence for ketamine is less clear: while ketamine improves anhedonia and quality of life, persistent emotional blunting has rarely been assessed directly, so the main limitation is a lack of measurement rather than negative findings.

Interpretation across studies was limited by inconsistent outcome measures, sparse long-term comparative data, and variable definitions and instruments. SSRI research uses blunting-specific tools such as the Oxford Depression Questionnaire. In contrast, psychedelic studies often measure emotional breakthrough or altered-state phenomenology with instruments that are not harmonised with SSRI blunting scales. Despite limited evidence of direct comparisons, existing findings suggest that psilocybin may reduce depressive symptoms without the emotional blunting that limits SSRI tolerability and treatment satisfaction. However, superiority claims remain short-term and dependent on the measurement tool. Future trials should combine standardised blunting measures, depression severity ratings, behavioural emotional-processing tasks, and neuroimaging outcomes to separate drug effects from residual depression to clarify comparative efficacy and underlying mechanisms and determine whether effects persist beyond short-term follow-up in clinically representative patient samples.

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