What GLP-1 drugs do to depression and anxiety

Swedish records for ~100,000 people compared periods when the same individuals were and weren't taking GLP-1 medications.

Researchers used Swedish national health records to study nearly 100,000 people who already had depression or anxiety and were taking antidiabetic medication, comparing periods when the same individuals were and weren't using GLP-1 drugs like semaglutide and liraglutide. This "within-individual" design is a clever way to reduce bias, since it compares a person against themselves rather than against a different group of people. The findings ran counter to some earlier, more alarming reports: GLP-1 use was linked to a lower risk of worsening mental illness, including reduced psychiatric hospitalizations, fewer mental-health-related sick leaves, and more than a 40% lower risk of self-harm. Semaglutide specifically showed a 42% reduction in worsening mental illness compared to periods of non-use. This adds an important, large-scale data point to a previously mixed picture, some past studies had suggested these drugs might worsen mood, while this one suggests the opposite, though as an observational cohort study (not a randomized trial), it can show a strong association but can't fully prove the drugs are causing the improvement.