One of the cutting-edge cures for chronic muscle tremors is called a thalamic stimulator - it's a brain implant that delivers current to your thalamus. But it can also cause intensely pleasurable erotic feelings, leading one woman into implant addiction.
The 1986 case of a woman addicted to stimulating herself with a brain implant is chronicled in a scientific article from Pain journal called Compulsive thalamic self-stimulation: a case with metabolic, electrophysiologic and behavioral correlates. The unnamed woman had been suffering from chronic pain (the result of an injury) for over a decade, and had tried a number of drugs to deal with it. Though she was an alcoholic, doctors prescribed opium-based painkillers to her and she had been known to take more than her recommended dose. With her history of drug addiction, it's easy to see why doctors would have imagined that a brain implant would be the best course of action for the treatment of her chronic pain. Little did they know that the woman would become addicted to that, too.
Doctors implanted an electrode deep in her thalamus (see image below).
The article explains:
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.
What's interesting is that this case seems to have been largely forgotten, despite occasional mentions in the popular media over the years. Meanwhile, dozens of scientific articles have been published in medical journals about thalamic stimulators as a treatment for patients suffering from tremors caused by Parkinson's disease and Tourette's syndrome. There is likely some relationship between what our unnamed addict experienced (increased loss of motor control) and these new therapies (which help minimize loss of motor control).
Some evidence has turned up that thalamic stimulators are still delivering erotic feelings. A recent article in the International Journal of Impotence Research revealed that a patient who had received a thalamic stimulator to control his Tourette's was also getting erections when he self-stimulated with the implant. And a study of thalamic implants in sea bass showed that the fish underwent a "sex color change," part of their mating process, when stimulated.
Science fiction author Larry Niven once dubbed these addicts "wireheads," but science fiction has now become science fact. As thalamic stimulators and other brain implants become more commonplace, it's likely that our anonymous implant addict will no longer be an outlier. She's just the first documented case of a new kind of addiction.