The knowledge of the research field is developed from empirical data to theory, i.e. from the discovery by Thorell of an extraordinarily strong relationship between electrodermal hyporeactivity and suicide and attempted suicide with death intent1,2,3, to an empirically based hypotheses by Thorell about the mechanisms of preparedness and capability to take ones life4.

Thorell has shown, by analysis of own and other’s research results2 that suicidal patients with a diagnosis of depression are not able to elicit the specific electrodermal orienting reactions [READ MORE] reflecting normal curiosity, attention, to everyday life, which is required to learn the details of what is common, i.e. what is to be expected in a given situation. The lack of the electrodermal reactions is called electrodermal hyporeactivity.

The electrodermal reactivity was found to be completely normal in depressed patients who had not made any suicide attempt at any time in their life and had no current serious thoughts of suicide in contrast to depressed patients who had made at least one suicide attempt anytime in their life whose electrodermal reactivity was significantly lower1,2.

The hyporeactivity was shown to occur in up to 97% of depressed who later committed suicide (97 % sensitivity for suicide)2. Among depressed patients who were not hyporeactive, only 2 % took their life (98% specificity for suicide)3.

The occurrence (prevalence) of hyporeactivity in depressed patients who had become clinically assessed as having the lowest risk of suicide, i.e. those treated in outpatient psychiatric care, was
13 % (11 of 88) which is considerably lower than in depressed patients with the highest level of suicide risk, i.e. those who later took his own life, in which group the prevalence was 97% (28 of 29). This difference is extremely highly significant (p = 6.1-20)4, i.e. over eight hundred thousand trillion more strongly assured than what normally is considered to be statistically significant (p= 0.05) in opinion polling and in medical research.

These results allow the statements that

  • hyporeactivity is an almost necessary factor for the depressive suicide
  • reactivity may be an almost sufficient factor to prevent the depressive suicide.

Other research results show that

  • the electrodermal hyporeactivity persists still after recovery from depression6 and also in later episodes of depression3.
  • reactivity, by contrast, tends to convert into hyporeactivity in later episodes3.
  • the hyporeactivity is independent of
    • how deep the depressive state is2,3,
    • how successful the antidepressant treatment is (see review by Thorell2)
    • the time course of the depression – it remains at least one year5 and at least two years in remission6 and can become cronic3,
    • serotonin activity in the brain (level of 5 -HIAA in the cerebrospinal fluid) in psychiatric7 and schizophrenic8 patients, and independent of the effects of antidepressant drugs that increase the availability of serotonin in the brain (see review by Thorell2) .
    • gender and age between 18 and 65 years2,3.

The interpretation

of the results up to today4 is that brain hyporeactivity, concerning orienting reactions as measured by electrodermal method, seems to represent a previously unknown independent neuropsychological dysfunction which means that the hyporeactive is unable to react with curiosity and interest in and emotional attachment to everyday life events, probably leading to a psychological  condition of readiness to leave the perceived uninteresting life under strenuous conditions, such as strong negative perception of the self and the future. In addition to this risky condition, hyporeactivity may lead to an inability to be deterred by the pain and discomfort that the suicide attempt could mean, which gives the hyporeactive a psychological condition of capability to carry out the suicide.

However, the fact is that among those at least two thousands of patients that annually are judged to be at risk of suicide in Sweden, as few as 7-8 patients a year take their life during their health care or within a period of four weeks after last contact with the health care, a period when the risk is greatest4. This means that treatment and suicide prevention in collaboration with family, friends and society is effective4. On the other hand, only 1.4 % of those who take their life were discovered to be in risk of suicide9. The Swedish Board of Health and Welfare pointed out even earlier that the lack of assessment of suicide risk is by far the biggest reason that suicide occurs among patients10.

This means that

in so far as the assessment of suicide risk improves, the number of suicides and suicide attempts with intent to die is expected to decrease. Emotra’s EDOR Test is expected to strongly contribute to this, especially when applied systematically and strategically in primary and psychiatric care.

Emotra’s EDOR test is the only objective and clinically applicable method in the world to detect suicide risk.


1         Thorell LH, d’Elia G. Electrodermal activity in depressive patients in remission and in matched healthy subjects. Acta Psychiatr Scand. 1988; 78:247-53.

2         Thorell LH. Valid electrodermal hyporeactivity for depressive suicidal propensity offers links to cognitive theory. Acta Psychiatr Scand. 2009; 119:338-49.

3         Thorell LH, Wolfersdorf M, Straub R, Steyer J, Hodgkinson S, Kaschka WP, Jandl M. Electrodermal hyporeactivity as a trait marker for suicidal propensity in uni- and bipolar depression. Journal of Psychiatry Research, Accepterad, 2013.

4        Thorell LH, Eriksson T. Skyddar fysiologiskt mätbar nyfikenhet den deprimerade mot självmord? Manuskript för publikation, 2013.

5         Iacono WG, Peloquin LJ, Lykken DT, Haroian KP, Valentine RH, Tuason VB. Electrodermal Activity in Euthymic Patients With Affective Disorders: One-Year Retest Stability and the Effects of Stimulus Intensity and Significance. Journal of Abnormal Psychology. 1984; 93: 304-11.

6        Thorell LH, d’Elia G. Electrodermal activity in depressive patients in remission and in matched healthy subjects. Acta Psychiatr Scand. 1988; 78:247-53.

7         Edman G, Åsberg M, Levander S, Schalling D. Skin conductance habituation and cerebrospinal fluid 5-hydroxyindoleatic acid in suicidal patients. Arch Gen Psychiatry. 1986; 43 586–92.

8        Öhlund LS, Lindström LH, Öhman A. Electrodermal orienting response and central nervous system dopamine and serotonin activity in schizophrenia. J Nerv Ment Dis. 1992; 180:304-13.

9        Silfverhielm H. Självmord 2006–2008 anmälda enligt lex Maria. Stockholm: Socialstyrelsen; 2010. Artikel 2010-4-5.

10       Silfverhielm H. Självmord 2006–2008 anmälda enligt lex Maria. Stockholm: Socialstyrelsen; 2010. Artikel 2010-4-5.