Filip Bouckaert

Sustained mood improvement with laughing gas exposure (SMILE): a randomised, placebo-controlled pilot trial of nitrous oxide for treatment-resistant depression: commentary, Kalmar et al

BJPsych Open July 1, 2026 Alain F. Kalmar, Pascal Sienaert, Filip Bouckaert et al.

Summary Nitrous oxide is being investigated as a treatment for therapy-resistant depression, yet its environmental implications as a potent greenhouse gas are largely unaddressed. A single 1 h treatment generates ∼150 kg CO 2 -equivalents, rising to ∼7.8 t per patient-year, highlighting the need to incorporate environmental externalities into evaluation.