Medical marijuana has the potential be used to treat depression caused by chronic stress, researchers have said.

In a study looking at endocannabinoids – chemicals in the brain similar to substances found in cannabis – scientists found chronic stress its reduced the production, which led to depression-like behaviour in animals studied.

The team, from the University at Buffalo's Research Institute on Addictions in New York, noted that endocannabinoids are a naturally produced chemical compound that affect motor control, cognition, emotions and behaviour.

They are similar to the chemicals found in marijuana and the active ingredient in it – THC (delta-9-tetrahydrocannabinol).

Senior researcher Samir Haj-Dahmane said: "Chronic stress is one of the major causes of depression. Using compounds derived from cannabis — marijuana — to restore normal endocannabinoid function could potentially help stabilise moods and ease depression."

Their findings were published in the Journal of Neuroscience.

Haj-Dahmane said they now plan to find out if the marijuana extract cannabidiol (CBD) restores normal behaviours in animals, without leading to dependence.

However, he added they are nowhere close to the drug being used in humans.

"Our research thus far has used animal models; there is still a long way to go before we know whether this can be effective in humans. However, we have seen that some people who suffer from post-traumatic stress disorder have reported relief using marijuana."

Medical marijuana is currently legal in 23 states, where it can be used for conditions like multiple sclerosis and glaucoma.

Scientists across the globe are currently working to test its use on a range of conditions, with previous findings showing it can be used to reduce brain tumour size, prevent post-traumatic stress disorder symptoms and reduce seizures in Dravet Syndrome.