Desperate Living (1980) on Netflix

In an affluent Baltimore suburb, all hell is about to break loose in the home of the Gravels. Bosley Gravel (George Stover) has a discussion on the front porch with Dr. Evans (Al Strapelli). Gravel has had his wife Peggy (Mink Stole) released from a mental institution; Evans feels she should have stayed for a while longer, but Gravel says that Peggy's breakdown is "part of the past now". However, inside the house, Peggy is in hysterics. Her young son and his friends are playing baseball in the front yard, and one of them accidentally hits a baseball through Peggy's window. She immediately starts shrieking and views the accident as an assassination attempt. She begins screaming at the children, then is driven even further insane when the phone rings and it's a wrong number. She viciously berates the caller and goes downstairs. Grizelda Brown (Jean Hill) is a very large black woman who works as a maid for the Gravels; she is doing housework when Peggy appears in her frantic state. Grizelda assures her that everything is alright and she's just upset, but Peggy tells her that someone just tried to kill her.