Perception to laser heat stimuli in depressed patients is reduced to Aδ- and selective C-fiber stimulation

► We assessed C- and Aδ-fiber systems in depressed patients and healthy controls. ► Patients showed elevated pain thresholds and significantly less C-fiber responses. ► Patients failed significantly more often to recognize the noxious laser-heat stimuli. ► Results suggest differential processing of painful information in depressed patients.