Electrodermal Activity (EDA) refers to changes in electrical conductance of the skin. Electrodermal hyporeactive individuals are those who show an unusual rapid habituation to identical non-significant stimuli. Previous findings suggested that electrodermal hyporeactivity has a high sensitivity and a high negative predictive value for suicide. The aim of the present study is to test the effectiveness and the usefulness of the EDOR® (ElectroDermal Orienting Reactivity) Test as a support in the suicide risk assessment of depressed patients.

One thousand five hundred and seventy three patients with a primary diagnosis of depression, whether currently depressed or in remission, have been recruited at 15 centres in 9 different European countries. Depressive symptomatology was evaluated through the Montgomery-Asberg Depression Scale. Previous suicide attempts were registered and the suicide intent of the worst attempt was rated according to the first eight items of the Beck Suicide Intent Scale. The suicide risk was also assessed. During the EDOR® Test two fingers are put on gold electrodes and a moderately strong tone is presented through headphones now and then during the test. The EDOR® Test is able to register the electrodermal responses to those tones, along with the blood volume in the fingers. Each patient is followed up for one year in order to assess the occurrence of suicidal behaviors.

Expected results would be that patients realizing a suicide attempt with a strong intent or committing suicide should be electrodermally hyporeactive in most cases and non-hyporeactive patients should show only few indications of death intent or suicides. Preliminary findings will be presented.