A Denver-based company hopes to be the state’s first to study the effects of marijuana on Alzheimer’s disease, thanks to a newly available research and development license in the city. MedPharm Holdings plans to apply for a Denver marijuana R&D license to test delta-9 tetrahydrocannabinol (THC), cannabidiol (CBD) and other cannabinoids’ effects on Alzheimer’s and dementia patients. According to the Alzheimer’s Association, 5.8 million Americans have the disease, a degenerative brain disorder that affects a person’s memory and thinking skills.