Deep Brain Stimulation (DBS) is a treatment involving the implantation of electrodes into the brain. Presently, it is used for neurological disorders like Parkinson’s disease, but indications are expanding to psychiatric disorders such as depression, addiction and Obsessive Compulsive Disorder (OCD). Theoretically, it may be possible to use DBS for the enhancement of various mental functions. This article discusses a case of an OCD patient who felt very happy with the DBS treatment, even though her symptoms were not reduced. First, (...) it is explored if the argument that ‘doctors are not in the business of trading happiness’, as used by her psychiatrist to justify his discontinuation of the DBS treatment, holds. The relationship between enhancement and the goals of medicine is discussed and it is concluded that even though the goals of medicine do not set strict limits and may even include certain types of enhancement, there are some good reasons for limiting the kind of things doctors are required or allowed to do. Next, the case is discussed from the perspective of beneficence and autonomy. It is argued that making people feel good is not the same as enhancing their well-being and that it is unlikely—though not absolutely impossible—that the well-being of the happy OCD patient is really improved. Finally, some concerns regarding the autonomy of a request made under the influence of DBS treatment are considered. (shrink)