Addiction To Placebos
A 38-year-old married schizophrenic was in psychotherapy for severe depression and multiple suicide attempts. She was addicted to methylphenidate, taking 25 to 35 10-mg pills per day. She was incredibly adept at persuading pharmacists to refill old prescriptions. With the help of her husband and a drug company, placebos were gradually substituted for the real pills to the point where only two real pills and 25-30 placebos were taken each day. The patient never noticed, indicating that the placebos satisfied the patient's real need-- something to fill an inner void.
(Muntz, Ira; "A Note on the Addictive Personality: Addiction to Placebos." American Journal of Psychiatry, 134: 327, 1977.)