Deep brain stimulation almost halves the symptoms of obsessive-compulsive disorder in patients whose condition is severe and treatment-resistant, according to findings from the largest meta-analysis to date.

US researchers say the invasive technique can also provide substantial relief of comorbid depressive symptoms, with almost two-thirds of recipients considered full or partial responders.

The researchers from Baylor College of Medicine in Houston, Texas caution, however, that 31% of patients had one or more serious adverse events, including suicide.

In their review of 34 studies, they analysed data from 352 adults (mean age 41) with severe to extreme obsessive-compulsive disorder (OCD) at baseline and who had failed to respond to pharmacotherapy and psychotherapy.