The mirror drawing test (MDT) was performed to induce acute psychological stress in 10 normal volunteers and 23 neurotic patients. Plasma cAMP and cyclic guanosine 3',5'-monophosphate (cGMP) were determined serially before, during, and after the test. In controls, the MDT caused a significant increase in the plasma cAMP level, whereas no change was observed in plasma cGMP. This increase was suppressed by simultaneous administration of propranolol, although it was not affected by simultaneous injection of phentolamine. In neurotic patients, the instruction for the MDT itself resulted in increased cAMP and cGMP levels, although there were no further significant increases during and after the MDT. The results indicate: 1) the increase in plasma cAMP during the MDT reflects a beta-adrenergic stimulation; 2) in neurotics, the response of cAMP and cGMP to the MDT is different from the controls. This difference may be a potential parameter in the diagnosis and discrimination of neurotic disorders.