Breath Metabolomics of Placebo Effects, a Pilot Study

Interrogation of the exhaled breath metabolome will be performed by using an objective method of measurement for placebo effects in pain analgesia, known as Cold Pressure Test (CPT). CPT reactions can be measured objectively by blood pressure spikes as well as changes in continuous heart rate monitoring.To this end, probands will be continuously connected to a Heartrate & Blood Pressure Monitor. First, baseline exhalation will be assessed. Then, the CPT is performed according to the 'CPT Guide' with subsequent post-pain exhalations analysis with or without self-administration of the placebo (NaCl nasal spray). After 15 minutes rest, probands will be submitted to a second post-pain exhalations set (+/- placebo). The process is completely non-invasive as the participant just exhales through a commercially available disposable bacterial/viral filter coupled to the ion source.

Inclusion criteria

• Healthy female and male adult volunteers
• German speaking, or good knowledge of the German language
• Able to understand the study
• Able to give informed consent

Exclusion criteria

• Regularly taking medication potentially interfering with pain sensation (analgesics, antihistamines and calcium and potassium channel blockers)
• Current pregnancy
• Daily smokers (as per WHO definition: A daily smoker is someone who smokes any tobacco product at least once a day.)
• Neuropathy
• Chronic pain
• Neuromuscular or psychiatric disease
• Known or suspected heart, kidney or liver disease
• Hypertension (Systolic (mmHg) >130, Diastolic (mmHg) >80)
• History of fainting or seizures
• History of Frostbite
• Current medications (psychoactive medication, narcotics, intake of analgesics) or being currently in psychological or psychiatric treatment.