NMD can cause:

• headaches, which may be severe and last for some days
• weight gain (this is associated with subcaudate tractotomy and bilateral anterior capsulotomy, but not with bilateral anterior cingulotomy – no one knows why)
• apathy (a lack of emotion, interest or concern). One study on people who received subcaudate tractotomy for depression suggested that although they were not depressed afterwards, they seemed not to care anymore about difficult issues that might have upset them in the past. This effect is not seen in people who have more common treatments for depression.

In addition to this, all brain surgeries carry a risk of causing:

• damage to the blood vessels (which may result in stroke, although this is very rare in NMD)
• confusion
• epilepsy (a neurological condition which causes seizures)
• pressure in the front of your brain, caused by fluid produced in the brain tissues as part of the healing process. This can make you feel confused, and can last for up to a month after the operation.

Could NMD affect my mental capacity or personality?

• Mental capacity – there is no evidence that NMD causes any loss of thinking ability. It might actually have the outcome that you're able to think more clearly, probably because of the relief of symptoms that had previously made it hard for you to concentrate.
• Personality – personality changes following NMD have been reported in some people, but are considered rare.

This information was published in May 2015. We will revise it in 2018.