Mind Hacks found this research paper from 1986 about a 48-year-old woman who received a deep brain stimulation implant to help her cope with chronic pain.
Soon after insertion of the nVPL electrode, the patient noted that stimulation also produced erotic sensations. This pleasurable response was heightened by continuous stimulation at 75% maximal amplitude, frequently augmented by short bursts at maximal amplitude. Though sexual arousal was prominent, no orgasm occurred with these brief increases in stimulation intensity. Despite several episodes of paroxysmal atrial tachycardia [heart disturbance] and development of adverse behavioural and neurological symptoms during maximal stimulation, compulsive use of the stimulator developed.
At its most frequent, the patient self-stimulated throughout the day, neglecting personal hygiene and family commitments. A chronic ulceration developed at the tip of the finger used to adjust the amplitude dial and she frequently tampered with the device in an effort to increase the stimulation amplitude. At times, she implored her to limit her access to the stimulator, each time demanding its return after a short hiatus. During the past two years, compulsive use has become associated with frequent attacks of anxiety, depersonalization, periods of psychogenic polydipsia and virtually complete inactivity.