Clinical trial NCT02157389: Psychobiological Mechanisms of Placebo and Nocebo Effects in the Treatment of Chronic Back Pain
Official title: Psychobiological Mechanisms of Placebo and Nocebo Effects in the Treatment of Chronic Back Pain
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Chronic Lower Back Pain
Healthy Control Subjects
Lead sponsor: Central Institute of Mental Health, Mannheim
Sponsor class: OTHER
First posted: 2014-06-06
Enrollment: 80
Sex: ALL
Minimum age (years): 18
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: BASIC_SCIENCE

Brief summary: Placebo and nocebo responses have mainly been studied in healthy humans for pharmacological rather than psychological interventions. Moreover, only few studies examined patients or tested how previous experience and attitudes affect placebo and nocebo responses. On the psychological level expectancy and classical conditioning have been identified as two primary mechanisms. Both seem to be important with classical conditioning potentially having more long-term effects and expectancy being more important in nocebo effects. There is some initial evidence from the investigators own research that patients may be more prone to these effects and the investigators have also shown that placebo effects may last up to several years after treatment. The investigators therefore examine previous attitudes to pharmacological interventions for chronic pain in patients with chronic back pain and subdivide them into groups with high of low belief in the respective treatment modality. The investigators then apply a pharmacological placebo and study the interaction between the prevailing attitude (implicit and explicit) and the placebo effect with respect to pain perception but also to neurobiological mechanisms using functional magnetic resonance imaging. In addition to expectancy, conditioning of placebo will be examined and the long-term effects of the intervention will be determined.


Eligibility criteria: Inclusion Criteria:

* Male and female human subjects with chronic back pain (chronic persistent and recurrent pain \> 6 months)
* Age between 18 and 65
* Voluntary participation.

Exclusion Criteria:

* Acute or chronic somatic diseases and inflammatory, neuropathic or tumor-related pain
* Acute and chronic mental disorders according to DSM-IV (except for comorbid anxiety or depression, which are frequent in chronic pain)
* Insufficient German language skills
* Cognitive limitations
* Intake of opioid medication or tranquilizers
* Metal implants or electric implants that cannot be removed
* Pregnancy
* Claustrophobia
* History of epilepsy, brain trauma, or brain tumor

Primary outcomes:
measure: Changes in pain intensity and pain unpleasantness ratings after placebo intervention
timeFrame: immediatey to one week
Secondary outcomes:
measure: Changes in neuronal activity in response to painful stimulation after placebo administration
timeFrame: immediately
measure: Changes in movement abilities after placebo administration
timeFrame: immediately to one week
Other outcomes:
Locations:
city: Mannheim
country: Germany
facility: Central Institute of Mental Health
Study officials:
affiliation: Medical Faculty Mannheim, Heidelberg University
name: Herta Flor, PhD
role: PRINCIPAL_INVESTIGATOR
References: