Ketamine is an anesthetic drug that is sometimes used to relieve chronic pain. The goal of this observational study is to learn about how patients respond to ketamine infusions for chronic pain.

Note: This study does not provide ketamine - instead, this study uses surveys to follow patients who are already scheduled to receive ketamine infusions as part of their regular medical care.

We will also follow a second group of patients who were recommended ketamine infusions by their doctor but were denied insurance coverage for this treatment. These participants will complete the same surveys for up to 16 weeks, starting from when their treatment was originally scheduled. Comparing this group to patients who received ketamine will help researchers better understand ketamine's effects and how insurance denials affect chronic pain patients.

Some key questions this study would like to answer:

1. How do patients respond to ketamine over time? This study will use surveys to track pain, sleep, mood, function, and other experiences for up to 16 weeks after a ketamine infusion.
2. Does the dose matter? This study aims to find out whether patients who get higher doses of ketamine have longer-lasting pain relief, and whether there is a point of diminishing returns.
3. What makes some patients respond better than others? For example, there are some early data suggesting that patients who worry more about their pain might have more trouble reducing their opioids after ketamine treatment even if they had pain relief.
4. Are ketamine infusions addictive when used for pain treatment? This study will track cravings and drug liking for up to 16 weeks after a ketamine infusion. Addiction risk is expected to be low, but this study will document this risk systematically.
5. What happens to patients who were recommended ketamine but denied insurance coverage? This study will compare their outcomes to patients who received ketamine, to better understand the impact of insurance denials and the real-world effects of ketamine treatment.

STUDY PROCEDURES SUMMARY

Upon consenting to the study, eligible participants will be asked to share their contact information, some background health information, details about their scheduled infusion, prior ketamine experience, and baseline symptoms. All personal information will be kept private and secure. Participants will be assigned a unique study number, and their name and contact details will not be shared with anyone outside the core study team.

Afterwards, participants will:

• Complete an online survey a few days before their infusion; then one survey each week for up to 16 weeks after their infusion. These surveys will track pain, mood, sleep, medication use, and other symptoms over time.
• Optionally allow the study team to review medical records related to their ketamine treatment (such as the ketamine dose, side effects, and diagnoses linked with treatment).
• Patients who were recommended ketamine but denied insurance coverage will have to opportunity to complete the same surveys

Inclusion Criteria:

• Planning to receive an intravenous ketamine infusion for the treatment of chronic pain

Exclusion Criteria:

• Unable to read or understand English questionnaires

Adults who have had a treating physician order ketamine infusion therapy for the treatment of chronic pain

Upon publication of study results with no end date

A proposal that describes planned analyses must be approved and a data sharing agreement must be signed before accessing IPD from the study team