Whilst hanging is a fairly reliable method if carried out correctly, there are a number of things that can go wrong, many of which are likely to result in permanent brain damage. So read carefully, as they are all to be avoided:

  1. Rope, or whatever it is attached to, breaking. If this happens before the onset of death, there is high probability that brain damage will occur (unless the rope breaks very soon after the attempt commences). Note that the body will thrash around both conscious and unconscious, which could increase the chance of a breakage in whatever is used to achieve suspension.
  2. Discovery before the onset of death. Implications are as for 1 above.
  3. In drop hanging, drop not long enough to break the neck. This will result in an unpleasant suspension hanging where there is intense pressure on the neck.
  4. In drop hanging, blood flow to/from the head only partially obstructed. This will delay the onset of unconsciousness and death, whilst potentially cutting off the air supply, making death particularly unpleasant. Getting the knot right is important to try and avoid this.
  5. In short drop/suspension hanging, in addition to brain damage, there is also the possibility of heart and/or lung injury.

If carried out correctly though, the certainty of death with this method is very high, providing it is not interrupted before completion. This method is totally unsuitable for a suicidal gesture.