Betty Berzon, a psychotherapist and author who championed gay rights after struggling for more than half her life with her own sexuality, has died, according to the Associated Press. She was 78.

Berzon died at her San Fernando Valley home in California on Jan. 24, said her longtime partner Teresa DeCrescenzo. She stated that Berzon had battled breast cancer for many years.

Berzon’s works include the best-selling Permanent Partners: Building Gay and Lesbian Relationships That Last, Advocate.com reported. Published in 1988, the book was one of the first to advise gay couples on issues such as financial burdens and having children. Berzon was editor of 1979’s Positively Gay: New Approaches to Gay and Lesbian Life, which has never gone out of print and was expanded, updated and revised in 2001.

She wrote of her own dramatic struggle with self-loathing in her Lambda Literary Award-winning 2002 autobiography, Surviving Madness: A Therapist’s Own Story, which chronicled her journey from suicidal psychiatric patient to self-assured gay-rights activist and successful author. As an activist, Berzon founded Southern California Women for Understanding, a nonprofit lesbian organization still in operation, in 1976. She served on the board of directors of National Gay Rights Advocates and was president of the Gay Academic Union.