The Park County, Montana coroner’s office has ruled Margot Kidder’s death a suicide.

In a statement provided to The Associated Press Wednesday, Coroner Richard Wood said Kidder’s death was “a result of a self-inflicted drug and alcohol overdose.” No further details were released.

Kidder, who is probably best known for portraying Lois Lane opposite Christopher Reeve in the 1970s and ’80s Superman movies and starred in many other films including The Amityville Horror, died May 13 at her home in Livingston, Montana, at the age of 69.

Kidder struggled with mental illness through a good part of her life, a situation that was made worse by a 1990 car crash that left her in debt and led to her using a wheelchair for almost two years. She continued to work as an actress throughout, including a six-episode role on Boston Common in 1996-97. Her most recent role was in 2017 with the indie The Neighborhood.