Human Brain Adaptation to Chronic Pain and Its Effects on Opioid Use

The prevalence of chronic pain is very high in the US at approximately 30%. More than 10% of
adults report having daily pain. Opioid pain medications [such as morphine] are prescribed
for some pain conditions and, since they are very addictive, they can be used inappropriately
and abused, to the point of causing overdose and death. This is currently a significant
problem in the US and worldwide. Research on changes in the brain that cause addiction in
pain patients is complicated, also because it is difficult to separate the effect of the
drugs that cause addiction from the direct effect of pain on the brain. Studies in animals
have found that pain per se can change the brain in ways that increase the risk of becoming
addicted to pain medications. Therefore, we think that patients who have chronic pain and are
prescribed opioid pain medications to treat surgery-related pain after surgery, although they
never took opioids for a long time in their life, may be at increased risk of using too much
opioid medications, and using opioids for a longer time than expected to treat their surgical
pain.

The purpose of this study is to determine if the research results obtained in animal models
of pain (that show that being in pain for some time increases opioid use beyond what is
expected to treat the current pain) also apply to patients with chronic pain.

For our study we are looking to recruit patients scheduled for abdominal surgery at Barnes
Jewish Hospital. If eligible and enrolled, subjects will undergo sensory testing (a test of
the sensitivity of the skin to hot and cold temperature and pressure) and complete
questionnaires about their experience with pain, anxiety, depression and risk of substance
abuse. They will also have a one-time blood draw for genetic testing, to look for a
particular gene that is potentially associated with how we respond to pain medications and,
potentially, with increased risk for addiction. After the surgery, patients will be assessed
by the research team on day 1, week 1, week 4, week 8, and after 6 months with similar
questionnaires to those that were completed pre-surgery. Patient satisfaction with their
pre-surgical and post-surgical pain control will also be assessed by questionnaire.

Inclusion Criteria:

1. Age 18-65

2. With and without history of chronic muscle-skeletal pain *

3. Scheduled to undergo elective abdominal surgery requiring overnight hospital admission

4. Opioid naïve**

5. Willing to comply with study procedures as outlined in the protocol

6. Willing and able to provide informed consent

7. Having an email address and access to a computer or electronic tablet

Exclusion Criteria:

1. Current use of opioids (includes ANY use in past 3 months)

2. Cancer diagnosis

3. Patient presenting the following documented conditions:

Untreated psychosis Current suicidal ideation Current substance abuse