• 1922  Pioneering feminist Emily Murphy publishes an inflammatory book, The Black Candle. She claims that marijuana turns its users into homicidal maniacs.

• 1923  Cannabis is added to the Schedule of the Opium and Narcotic Control Act.

• 1969  Canadian government establishes a Commission of Inquiry Into the Non-Medical Use of Drugs, known as the Le Dain commission after its chairman, Gerald Le Dain.

• 1972  The commission recommends decriminalizing simple cannabis possession and cultivation for personal purposes.

• 1976  The Netherlands effectively decriminalizes marijuana.

• 1977  Then-prime minister Pierre Trudeau tells a group of students: "If you have a joint and you're smoking it for your private pleasure, you shouldn't be hassled."

• 1978  New Mexico passes the first state law recognizing the medical value of marijuana.

• 1996  California becomes the first state to legalize medical marijuana.

• 1999  Two Canadian patients get the federal OK to smoke pot.

• 2000  Court rules Canadians have a constitutional right to use cannabis as a medicine.

• 2001  Canadian Medical Marijuana Access Regulations grant legal access to cannabis for individuals with HIV/AIDS and other illnesses. Authorized patients can grow their own pot or obtain it from authorized producers or Health Canada.

• 2012  Ballot measures in Colorado and Washington legalize recreational use of small amounts of marijuana.

• 2013  New regulations change the Canadian medical marijuana access rules, shifting to licensed commercial growers for supply and away from homegrown. Some 37,800 people authorized to possess marijuana under the federal program, up from fewer than 100 in 2001.

• 2014  The federal government says the unforeseen growth of its medical marijuana program has “seriously compromised” the goal of providing the drug to patients while ensuring public safety. It says the number of people authorized to possess marijuana under the federal program has risen to 37,000 from fewer than 100 in 2001.

• 2014  Patients and producers authorized under the old regulations required to destroy stocks of pot and cannabis seeds, although a Federal Court has granted a temporary injunction allowing continued use of home-grown medical marijuana until legal arguments can be heard.