Physiologic responses to loud tones in individuals with obsessive-compulsive disorder.

OBJECTIVE To determine if individuals with obsessive-compulsive disorder (OCD) are characterized by larger eyeblink and/or autonomic responses to sudden, loud (startling) tones. METHODS Twenty participants with OCD and 21 mentally healthy control participants were presented with 15 consecutive 95-db, 500-msec, 1000-Hz tones with 0-msec rise and fall times at the same time orbicularis oculi electromyogram (EMG), heart rate (HR), and skin conductance (SC) responses were measured. RESULTS Participants with OCD produced larger average HR responses and a slower decline in SC responses across the 15-tone presentations. A trend for larger than average eyeblink EMG responses in participants with OCD was also observed. CONCLUSION These results provide laboratory support for enhanced HR reactivity and a slower decline in SC responses to startling stimuli in individuals with OCD.