LONDON – A marijuana pill appeared to relieve some of the symptoms of multiple sclerosis in the first scientifically rigorous study of the strongly debated drug.

The research, published this week in The Lancet medical journal, found that even though improvements could not be detected by doctors’ tests, a greater proportion of patients taking the drug reported reduced pain and muscle stiffness than those taking fake capsules.

Experts said the mixed results make them tricky to interpret. Some said they were encouraged any improvement was noted, while others said if there had been a major effect, it would have shown up in the doctors’ tests.

One study leader, Dr. John Zajicek of the University of Plymouth in England, said the research raises questions about what’s more important: a doctor’s measurements or the patient’s perspective.

Multiple sclerosis, a common nervous system disease, causes a range of chronic symptoms, including muscle stiffness and spasms, pain, tremor, fatigue, depression and bladder problems.