Discrepancies between subjective and physiological stress levels may help to explain why stress leads to psychosis. We examined self-reported and physiological stress levels (heart rate, skin conductance level, cortisol level) during two conditions (noise stressor, no stressor) in patients with psychotic disorders (n = 35), patients with depression (n = 30), and healthy controls (n = 28), expecting larger discrepancies between self-reported and physiological stress levels in patients with psychosis than in controls. Difference values were calculated from standardized stress levels. Compared to healthy controls, patients with psychosis showed larger discrepancies between self-reported stress and skin conductance levels and between self-reported stress and cortisol levels. The discrepancies were similar in both patient groups and in both conditions. Paranoid symptoms, emotion awareness and antipsychotic dose were associated with the discrepancies. Future research needs to clarify whether the discrepancies causally contribute to psychotic symptoms or reflect secondary processes.
