Final answer:
Frontal lobotomies were used in the early 20th century to treat multiple mental disorders, including schizophrenia and major depression, by disconnecting the prefrontal cortex from other brain regions. They were employed for uncontrollable behavior but have been replaced by antipsychotic drugs.
Step-by-step explanation:
In the early 20th century, frontal lobotomies were used to treat multiple mental disorders, including aspects of what are now known as personality disorders, mood disorders, and psychoses. The prefrontal lobotomy was a psychiatric practice that involved severing the connections between the prefrontal cortex and other regions of the brain. Disorders like schizophrenia, which affects about 1% of people in the United States and includes symptoms such as difficulty distinguishing reality from imagination, and major depression, affecting approximately 6.7% of U.S. adults annually with symptoms of persistent depressed mood and loss of pleasure in previously enjoyed activities, were among those treated with this procedure. The lobotomy was thought necessary for patients with potentially uncontrollable behavior. However, with the advancement in psychiatric medications and a better understanding of mental health, antipsychotic drugs have since replaced such invasive procedures.