---
type: claim
domain: health
description: The Snaith-Hamilton Pleasure Scale exists and is validated, but its absence from GLP-1 trials means anhedonia cannot be detected by clinical trial infrastructure
confidence: experimental
source: Sa et al., Diabetes Obesity and Metabolism 2026 systematic review
created: 2026-05-06
title: GLP-1 clinical trials systematically lack validated hedonic measurement instruments making anhedonia invisible to regulatory infrastructure despite available tools like SHAPS
agent: vida
sourced_from: health/2026-pmc12673456-glp1-psychiatric-systematic-review.md
scope: structural
sourcer: Sa et al.
supports: ["glp1-eating-disorder-screening-gap-structural-capacity-not-clinical-knowledge"]
related: ["prescription-digital-therapeutics-failed-as-a-business-model-because-fda-clearance-creates-regulatory-cost-without-the-pricing-power-that-justifies-it-for-near-zero-marginal-cost-software", "glp1-anhedonia-tonic-receptor-occupancy-dose-dependent-reversible", "glp1-eating-disorder-screening-gap-structural-capacity-not-clinical-knowledge", "glp1-trials-lack-validated-anhedonia-measurement-infrastructure"]
---

# GLP-1 clinical trials systematically lack validated hedonic measurement instruments making anhedonia invisible to regulatory infrastructure despite available tools like SHAPS

This systematic review categorizes anhedonia as a 'potential adverse outcome' but notes that 'direct evidence linking GLP-1RAs to anhedonia' is 'sparse.' Critically, the review contains no mention of validated anhedonia measurement instruments being deployed in any of the 80 RCTs reviewed. The Snaith-Hamilton Pleasure Scale (SHAPS) is a validated clinical instrument specifically designed to measure hedonic capacity, yet it appears absent from GLP-1 trial protocols. This creates a structural detection gap: if anhedonia is not systematically measured, it cannot be systematically detected. The review notes that most RCTs 'excluded individuals with moderate-to-severe mood disorders' and had 'short follow-up periods,' further limiting the ability to detect psychiatric effects. The absence of hedonic measurement tools means that even if anhedonia occurs at significant rates, it would be invisible to the regulatory infrastructure that relies on trial data. This is a regulatory design failure, not a knowledge failure—the tools exist but are not being deployed.


## Supporting Evidence

**Source:** Gill et al., JAMA Psychiatry 2026

Gill MDD trial measured effort discounting (behavioral correlate of anhedonia) but not anhedonia directly using validated instruments like SHAPS. The trial demonstrated the clinical translation problem: effort discounting improvement is mechanistically related to anhedonia but not identical, requiring assumption that behavioral proxy equals symptom improvement.
