Past Pain Experience and Perception of Experimental Pain

Differences in pain perception between subjects with and without psychiatric illness may be influenced by the individual experience, and not primarily by the pathology, although the pathological frame may amplify it.The aim of this study is to establish if the characteristics of experimental pain feeling are influenced by the past pain experience, anxiety and emotion, independently from the diagnosis. The pain experience will be evaluated by an inventory of the potentially painful situations that one can come across through the life, to determine the following points : Number of painful events in the past, number of painful points during the last 6 months, number of painful events lasting more than 6 months, sum of pain intensities (graduated with Visual Analogic Scale VAS from 0 to 10), sum of gravity (evaluated from 0 to 5), the category of pain experience qualification (mostly affective, mostly sensorial, or both).

Schizophrenic, depressed and control participants will be recruited, and their pain experience throughout life will be put it in relation to experimental pain tests results (pressure application, ischemia induction), anxiety and emotion (Hospital Anxiety and Depression scale HAD), catastrophizing (Pain Catastrophizing Scale PCS), Heart Rate (HR) variation, Blood Pressure (BP) variation.

The perception of moderated experimental pain (about 3 out of ten with visual analogue scale VAS) in subjects with schizophrenia (Girard et coll., 2011), major depression (ED) (bipolar or isolated/recurrent episode) (to be published) in comparison with controls without psychiatric pathologies show that exploration of pain in situation like medical examination to identify painful points should be done in the same conditions for persons with psychiatric troubles and persons without mental disease. But the risk is that the expression of pain, either in experimental conditions nor in the daily life, is not in relation with the feeling or perception of pain. Numerous factors may interfere in the pain message modulation, like the past pain experience, stress and anxiety, which are not or partially explored in experimental studies. The individual experience of pain is constructed throughout the whole life, from several influences (biological, psychological, and sociocultural). The symptoms interfaces of the different psychiatric troubles seem to be widely involved in the pain process, and its progressive construction. This study aims to better understand the relationships between all those variables.

Procedures applied :

Anterior pain experience evaluation (questionnaire); Pain tests : 160 kPa pressure application to determine corresponding pain with VAS), and ischemia induction to determine the time necessary to obtain a pain equivalent to 3 out of 10; anxiety and emotional evaluation (Hospital Anxiety and Depression scale), catastrophizing evaluation (Pain Catastrophizing Scale), HR variation and BP variation (vegetative measures linked to anxiety) collection of diagnosis, and therapeutic treatment

Eligibility Criteria:
Inclusion Criteria:

* subjects with psychiatric trouble : diagnosis of schizophrenia or major depression according to the DSM-IV-TR criteria.
* control subjects : without known psychiatric history.
* age between 18 and 60.

Exclusion Criteria:

* absence of consent, hospitalization under constraint, absence of health insurance.
* inability to answer the questionnaires
* pregnancy
* antalgic or analgesic treatment
* allergy to latex
* non stabilized high blood pressure, bad blood coagulation,
* peripheral neuropathy, nerve lesion, dermatosis at the superior extremities, muscular lesion or pathology at the upper member level
* non treated alcohol dependence
* illegal substance consumption in the past 48 hours
* participation to an other biomedical study during the 2 weeks before inclusion, and until the pain tests, if this study can interfere with the realization of the objectives