Polymer based therapies offer many potential advantages in the treatment of diseases of the nervous system, and would allow delivery of therapeutic agents directly to the relevant area of brain, circumventing obstacles presented by the blood brain barrier, avoiding the side-effects often associated with systemic medication administration, and permitting much smaller doses of medication. As improvements in diagnostic procedures, particularly imaging, now provide very accurate localization of therapeutic targets in many of these conditions, it is technically feasible to deliver such agents precisely to the relevant brain region. Combined with advances in polymer sciences, there is renewed interest in focal drug delivery systems, particularly around intelligent or controlled release systems which would extend the life-span of these devices considerably. Major obstacles remain, however, particularly around the safety and biocompatibility of such materials, and the complexity of testing in clinical scenarios. We review here the current status of animal and human studies in this rapidly evolving area, addressing some of the practical obstacles and examining the range of potential applications in chronic neurological disease.