Background There is very limited evidence for the efficacy of any specific therapeutic intervention in chronic, treatment refractory major depression. Thermal anterior capsulotomy (ACAPS) is a rarely performed but established therapeutic procedure for this patient group. While benefit has been claimed, previous ACAPS reports have provided limited information. Detailed prospective reporting of therapeutic effects and side effects is required.

Objective To report a prospective study of therapeutic effect, mental status, quality of life, social functioning and neurocognitive functioning in individuals with chronic treatment refractory major depression, treated with ACAPS.

Method A prospective case series of 20 patients treated with ACAPS between 1992 and 1999 were reassessed at a mean follow-up of 7.0±3.4 years. Data were collected preoperatively and at long term follow-up. Structural MRI was performed in 14 participants.

Results According to a priori criteria, at long term follow-up, 50% were classified as ‘responders’ and 40% as ‘remitters’. Fifty-five per cent were classified as ‘improved’; 35% were ‘unchanged’; and 10% had ‘deteriorated’. Neurocognitive and personality testing were not significantly different at follow-up. A trend towards improvement in some aspects of executive neuropsychological functioning was observed. Significant adverse effects were infrequent and there were no deaths.

Conclusions ACAPS may represent an effective intervention for some patients with chronic, disabling, treatment refractory major depression that has failed to respond to other therapeutic approaches. The adverse effect burden within this population was modest, with no evidence of generalised impairment of neurocognitive functioning.