The 1967 episode in New York was quite serious. [...] At Bellevue, she was initially placed with severely disturbed patients. She was physically restrained, heavily sedated, and underwent electroconvulsive therapy (ECT — "shock treatment").
—Nancy Princenthal on the book Agnes Martin: Her Life and Art
During the Coenties Slip years, she was hospitalised repeatedly. One winter, she fell into a trance in a church on Second Avenue, triggered when she heard the first few notes of Handel’s Messiah (although she loved music, it was often too emotionally stimulating). Another time, she was admitted to the notoriously chaotic Bellevue psychiatric hospital after being found wandering Park Avenue, uncertain of who or where she was. Before friends located her and had her moved to more salubrious environs, she was given shock therapy.