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 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.
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.
When studying the effects of different treatment and suicide prevention measures, it is of great importance to select those patients who are prepared to and capable to take their life and not to include patients who probably still would not take their life because of the protection by a normal neuropsychological orienting function.
- The method of Emotra is the only objective one that can manage to identify patients appropriate for such research.
Science in suicide becomes more and more focused on the damages and dysfunctions of the important brain structure hippocampus.
- The method of Emotra has, according to current theory, the potential to measure signs for suicide as a vital dysfunction in the hippocampus, irrespective of the cause.
Electrodermally hyporeactive persons do not react with normal curiosity about events in the everyday life.
- This leads to a condition of psychological preparedness to leave the life and capability to perform an attempt to do it which makes hyporeactives very vulnerable for suicide.
Electrodermally hyporeactive persons have difficulties to build clear memories of events in daily life. This may in turn lead to other cognitive dysfunctions, which can contribute to and worsen depression and quality of life.
- Emotra’s method is an objective functional method that could reveal deep neuropsychological causes of these dysfunctions.
Electrodermally reactivity tends to convert into hyporeactivity in next or later episodes of depression.
- Emotra’s method may be a tool to study the assumed brain damages that are believed to occur in recurrent depression.
EUDOR – A
More than 1,500 patients have been tested with EDOR® since we launched EUDOR-A, our European, clinical multi-centre study, in the autumn of 2014. As previously stated, the baseline material for EUDOR-A has been analysed. A scientific article, written last autumn and completed in the beginning of 2017, will shortly be submitted for publication in an international scientific journal.
An analysis of the results after one year’s follow-up of all tested patients shows that the individual test patients’ results weighted significantly in the clinics’ judgements, and they consistently elevated their risk assessments and degrees of suicide-preventive measures for those patients who were shown to be hyporeactive.
The number of suicides in the hyporeactive group decreased significantly, most likely thanks to these measures. All in all, only three suicides were observed in the hyporeactive group. According to our calculations based on the results from all previously carried out studies, many more suicides would have occurred in the hyporeactive group if the study had been blind. In other words, a number of hyporeactive patients’ lives have probably been saved. The number of suicides in the normally reactive group was very low, which is completely in line with expectations based on previous study results.
A study carried out by Lars-Håkan Thorell in collaboration with German researchers, comprising 783 patients tested in Ravensburg and with a follow-up period of 1–5 years, demonstrated a strong correlation between hyporeactivity and suicide. The Ravensburg study confirmed all observations made in previous, smaller clinical studies.
As a consequence of the already demonstrated strong correlation between hyporeactivity and suicide, a decision was made to set up the European multi-centre study, EUDOR-A, as a non-blind, naturalistic study. In light of the clear connection between hyporeactivity and risk of suicide, the clinics participating in the study, as well as their local ethical committees, did not deem it morally defensible to keep the clinics in the dark about individual patients’ test results.
During our review of the study results at the consensus meeting in Rome, we established that further analyses of the EUDOR-A study results, as well as more studies, should be carried out to increase our understanding of hyporeactivity’s significance for suicidal behaviour. A scientific exposition of the results and deeper analyses of the EUDOR-A study will be made in coming publications.
The total ratio of documented suicides in EUDOR-A is a record low and dramatically lower than in previous blind studies. A direct comparison with the Ravensburg study (where the follow-up period was up to 5 years) shows that while the suicide rate in that study was barely 5 percent, this rate plunged to appr. 0.5 percent, albeit after only 1 year’s follow-up in EUDOR-A. This reduction can most probably be explained by the directed suicide prevention measures that the clinics by their own accounts implemented to protect hyporeactive patients.
In all previous studies, the suicide rate has been distinctly higher among hyporeactive patients than among normally reactive patients. Likewise, the number of previous suicide attempts was higher among hyporeactive patients than among normally reactive patients.
The EUDOR-A results confirm both of these earlier observations. Despite the strong reduction in the number of suicides in the hyporeactive group (only three documented), the suicide rate for the hyporeactive group is clearly higher than for the normally reactive patient group.
However, these results are not statistically significant, since the suicide rates are so low (which is desirable) that they fall within the margin of error.
Nonetheless, the distinct difference in the number of previous suicide attempts is statistically very significant. A considerably higher suicide attempt rate was documented in the hyporeactive group compared with the normally reactive group.
All of these important observations confirm EDOR®’s central hypothesis: that hyporeactive patients are more vulnerable for suicidal actions than normally reactive patients.
A selection of scientific references
- 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: 586–592.
- Thorell LH. Electrodermal activity in suicidal and non-suicidal depressive patients and in matched healthy subjects. Acta Psychiatrica Scandinavica 1987; 76: 420-430.
- Thorell LH, d’Elia G. Electrodermal activity in depressive patients in remission and in matched healthy subjects. Acta Psychiatr Scand. 1988;78:247-53.
- Thorell LH, Kjellman BF, d’Elia G. Electrodermal activity in antidepressant medicated and unmedicated depressive patients and in matched healthy subjects. Acta Psychiatrica Scandinavica 1987:76:684-692.
- Thorell LH, Kjellman BF, d’Elia G. Electrodermal activity in relation to diagnostic subgroups and symptomatology of depressive patients. Acta Psychiatrica Scandinavica 1987:76:693-701.
- Keller FM, Wolfersdorf M, Straub R, Hole G. Suicidal behaviour and electrodermal activity in depressive inpatients. Acta Psychiatrica Scandinavica 1991; 83:324–328.
- Wolfersdorf M, Straub R, Hole G. Electrodermal activity in depressive men and women with violent or non-violent suicide attempts. Schweizer Archiv für Neurologie und Psychiatrie 1993; 144:173–184.1
- Wolfersdorf M, Straub R. Electrodermal reactivity in male and female depressive patients who later died by suicide. Acta Psychiatr Scand 1994; 89: 279–284.
- Diepers M. Zur Suizidalität in der Depression: Persönlichkeitsmerkmale und psychophysiologische Reaktionsmunster. [Personality traits and psychophysiological reaction pattern.] Dissertation. Ulm: Universität Ulm, 1994.
- Wolfersdorf M, Straub R, Keller F, Barg T. Elektrodermale Reaktivität bei Suizidversuch und Suizid Depressiver. [Electrodermal reactivity in suicide attempts and suicide in depressives.] In: Wolfersdorf M, Kaschka WP, eds. Suizid – Die biologische Dimension. [Suicide – the biological dimension] Berlin: Heidelberg, 1995; 99–110.
- Wolfersdorf M, Straub R, Barg T, Keller F. Depression und EDA-Kennwerte in einem Habituationsexperiment. Ergebnisse bei über 400 stationären depressiven Patienten. [Depression and electrodermal characteristics in a habituation experiment. Results from more than 400 depressive inpatients.] Fortschr Neurol Psychiatr 1996; 64: 105–109.
- Eriksson T, Nilsson M, Rawanduzi S, Thorell LH. Implementering av psykofysiologisk suicidriskdetektion vid Redakliniken AB, Linköping hösten 2007 – våren 2008. [Implementation of psychophysiological suicide risk detection at the Reda Clinic.] Landstinget i Östergötland [County of Östergötland], Redakliniken AB, 2008.
- Thorell LH. Valid electrodermal hyporeactivity for depressive suicidal propensity offers links to cognitive theory. Acta Psychiatrica Scandinavica 2009; 119: 338-349.
- 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. Insänt för publikation 2013.
- Thorell LH, Eriksson T. Skyddar fysiologiskt mätbar nyfikenhet den deprimerade mot självmord? Manuskript för publikation, 2013.