Cannabis consumers had "significantly better" outcomes than non-users.
77% of patients reported positive effects to researchers at Johns Hopkins University School of Medicine.
The endocannabinoid system is thought to be involved in mediating brain repair.
Dr Di Forti explains the motivations behind a new study hoping to explore the effects of cannabis on the brain.
Those who use cannabis are no more likely to lack motivation than people who don't, say authors.
Catch up on the latest global cannabis research.
Preliminary results suggest increased use may not be a bad thing.
While the number of legal prescriptions has grown significantly, most patients continue to self-medicate.
Previous cannabis use may be associated with lower risk of urological cancers.
Researchers are inviting UK families to share their experiences anonymously.