Neurosurgery for mental disorder (NMD) continues to exist as one of a range of treatments available to individuals who experience severe and intractable psychiatric illness. Historically, this particular use of ablative neurosurgery has attracted a considerable amount of interest and controversy. Despite modern advances in both technical procedure and understanding of the disorders for which NMD is indicated, the irreversibility of these procedures continues to attract attention from both public and professional groups alike. To date, indisputable evidence regarding the efficacy and frequency of adverse effects has not been established. Therefore, the primary aim of the present study was to investigate the neuropsychological outcome following neurosurgery for mental disorder. In light of previous research, the specific aims were designed to elucidate the impact of such procedures on aspects of both general and executive functioning, through means of clinical and computerised neuropsychological assessments. As such, pre- and post-operative performance scores of an entire population of surgical candidates at a national centre for the provision of NMD were examined. The principle investigation focussed on a group of 22 individuals of mixed diagnostic categories, all of whom had undergone treatment by anterior capsulotomy. Within-subjects comparisons revealed the overall stability of post-operative performance as measured by tests of general cognitive and executive function, at follow-up periods of two weeks, one year, and in a sub-group of individuals, two and a half years post-operatively. A small number of statistically significant improvements and impairments were noted, and along with the general trend of improvement observed at long term follow-up, are discussed in the light of related research.