Contact information for the prospective participants will be accessible only to the research staff according to HIPAA regulations. After completion of the online screening form, INPL personnel will contact eligible participants via phone and establish 100 total participants. After participants have been identified, INPL staff will schedule the participants' first visit. Eligibility requirements for this study are: medically diagnosed with MS, 21-74 years of age, and moderate disability (Patient Determined Disease Steps score 2-6). The investigators will recruit people with MS who are planning to use medical marijuana for the first time for the treatment of their symptoms. All participants must have a medical (red) card for medical marijuana use to treat their MS symptoms (such as neuropathic pain and spasticity), or currently be in the process of applying for a red card and be able to provide the prescription from their doctor. Marijuana and placebo cigarettes will be ordered from the NIDA (National Institute on Drug Abuse) Drug Supply Program and stored at a designated room in the Department of Health and Exercise Science (HES) at Colorado State University (CSU).