The authors studied 15 men who committed matricide. The majority were diagnosed as having chronic schizophrenia and had been living alone with their mothers. Other diagnoses included substance-induced psychosis and impulse disorders. Specific psychodynamic and environmental factors can be identified for each diagnostic category. The authors conclude that the matricidal impulse evolves through successive stages of psychological development; therefore, the motives for matricide are varied and correlate with the level of psychological development or regression.