The limited amount of true research completed has had mixed or conflicting results (some positive, some negative). On questionnaires, people often report benefit on pain, sleep, mood, or motor symptoms such as tremor or stiffness. But many also report side effects. This leaves patients, doctors and researchers with insufficient evidence to guide use.
Tetrahydrocannabinol (THC) is the principal psychoactive constituent of cannabis. In limited studies, THC has shown to improve both activity and hand-eye coordination in an animal model. A clinical study of 22 patients with the Parkenson’s and smoking marijuana, resulted in improvement of motor symptoms such as bradykinesia, resting tremor, rigidity, and posture, along with with non-motor symptoms such as sleep and pain.