Media playback is unsupported on your device Media caption A new study by the Pew Research Center found that most Americans favour treatment for drug users instead of jail time.

An exchange student fell to his death after ingesting marijuana in Colorado - the first death linked to the drug since it was legalised in the US state.

Levy Thamba, 19, plummeted from the balcony of a Denver hotel on 11 March after eating a cannabis-laced cookie.

A post-mortem examination found marijuana intoxication was a factor in the Wyoming student's death.

Colorado became the first US state to legalise recreational use of the drug in January.

Mr Thamba, a native of the Republic of Congo, had reportedly begun taking classes at Northwest College in Powell, Wyoming, the same month.

Currently, 20 US states as well as Washington, DC allow for the sale of medical marijuana, while Washington state is set to introduce legal sales later this year.

Recently, US President Barack Obama said marijuana was no more dangerous than alcohol, while cautioning both were bad decisions.

Nonetheless, he has instructed the Department of Justice to halt prosecutions of banks that do business with cannabis firms.