... with MS, sleep problems, and Parkinson's, study finds

• In New York, where the research team is based, marijuana is legal for medical use
• And a recent report found that most of the state's 98,000 medical marijuana users are aged 50 to 70

Medical marijuana eases pain, anxiety and sleep disorders in elderly people with neurological conditions, according to new research.

After just four months it helped those caused by chronic disorders including Parkinson's disease, multiple sclerosis, motor neuron disease and spinal cord or nerve damage, the study said.

About seven in ten (69 percent) reported some improvement after taking cannabis for four months.

The researchers found it was safe and effective, and it also caused a third of patients to reduce their use of highly-addictive opioids, that have killed more than 200,000 Americans in the last eight years.