Kidder was found May 13 in her home in the USA state of Montana.
As it was previously reported, the police discovered Margot passed away on the 13th of May in her home in Livingston.
In a joint statement, Kidder's family and the Park County Coroner's Office urged: '...those suffering from mental illnesses, addiction and/or suicidal thoughts to seek appropriate counselling and treatment'. While living in Montana, she was also an activist for progressive causes and animal rights. The Coroner has not specified what drugs she took.More news: Schwarzer: Kepa signing 'one hell of a statement'
In 1996, she was briefly homeless during her struggle and she became a very public advocate for mental health.
In what was an obvious reference to the Superman movies, Kidder made a cameo in Smallville along with the series' stars Michael Rosenbaum and Allison Mack.
"In her last months, she was herself - same kind of love, same kind of energy", Kesich said. A friend discovered Kidder's body at her home on May 13th. "The challenges that she had were very public". She wants to avoid any "cloud of shame".More news: Virat Kohli questions mentality of Indian top order
"The reality of my life has been grand and wonderful, punctuated by these odd blips and burps of madness", she said.
Both Kidder and co-star Christopher Reeve, who played Superman, were relative unknowns when they got their leading parts, and neither saw many major roles afterwards.
Most recently, Margot appeared in The Neighbourhood, which came out earlier this year.More news: China Slams 25-Percent Tariff On American Cars And Motorcycles