The effectiveness of Snoezelen| multi-sensory stimulation treatment was evaluated with 50 psychiatric patients (25 men, 25 women) and 50 hospital employees (25 men, 25 women). Pre and post-treatment physiological responses (galvanic skin conductance response, heart rate, and percentage blood oxygen) were compared and participants were evaluated post-treatment for perceived psychological benefits with a nine-item questionnaire. Results indicate that participation in a single 20-minute Snoezelen| session had significant and positive physiological effects on both the patient and staff groups. Also, post-treatment participants in both groups did not perceive any change on the dimension reserved-outgoing but felt more sleepy, passive, relaxed, cheerful, focused, optimistic, calm, and comfortable. Consequently, beneficial physiological and psychological Snoezelen| treatment effects were apparent for both patients and controls.