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Retinitis Pigmentosa progression may be slowed by cannabis

Medical ConditionAdverse effects


A 37 y/o PhD university research associate with retinitis pigmentosa found relief of associated symptoms with cannabis and subjective slowdown in progression of vision loss.


Vision loss, headaches, depression





Brief history and target symptomatology

This 37 y/o PhD university research associate was diagnosed with retinitis pigmentosa (RP) at age 14. He experiences progressive vision loss, headaches, depression and insomnia.

Previous and current conventional therapies

Supplementation with antioxidant vitamins was ineffective. Serial electroretinopathies (ERG) were discontinued in the belief that the flashes of light used further damage his retina and "ophthalmologists only want photographs for their own collection". His eyeglass prescription is reviewed annually to compensate for his increasing tunnel vision. He has not found significant improvement in his mood with psychotherapy.

Clinical response to Cannabis

Stress, mood, headaches and insomnia have all improved with cannabis use.

Additional Comments

RP is a genetic disease found in 1 in 4000 people in the US. In patient's case, it was traced to mutations in both parents' X chromosome. There is no known cure; valproic acid, gene therapy and retinal transplantation are currently in the research stage. Administration of a THC analog to rats with chemically induced RP has shown reduction in the rate of degeneration of retinal photoreceptors. .
Reference: Experimental Eye Research (2014), 120:175-185

Usual method of Cannabis administration


Frequency of Usage: Time Per Day


Frequency of Usage: Days per Week


Contributing Physician

Stefan Arnon, M.D.