Method and apparatus for treating and controlling neuropsychiatric disorders including schizophrenia, depression, and borderline personality disorder by selectively applying a predetermined electrical signal to the patient's vagus nerve for stimulation thereof to alleviate the symptoms of the disorder being treated. The electrical signal may be applied continuously, periodically, or intermittently to the vagus nerve depending, in part, on the nature of the disorder being treated. In certain instances, the electrical signal is applied upon detection of an event indicative of onset of the disorder. In other instances, the electrical signal is selectively applied at will to the vagus nerve, such as by patient activation of the signal generator. Parameter values of the electrical signal including pulse width, output current, frequency, on time and off time, are selectively programmable.