What is Macdonald’s Triad?

Macdonald’s Triad of Sociopathic Behaviour.

The Macdonald triad is a set of three behavioral characteristics which are associated with sociopathic behavior. In psychology, a combination of these behavioral characteristics are often found in the childhood histories of individuals with sociopathic behavior:

1. Enuresis (bedwetting) often past the age of 5;

2. Firesetting;

3. Torturing small animals;

 Individually, each of these characteristics are not clinically significant, but together they highlight an increased risk of future sociopathic behaviours.

The Macdonald triad is also known as the triad of sociopathy. It was first identified by a forensic psychiatrist, John Marshall Macdonald (November 7, 1920 – December 16, 2007), in a 1963 paper in the American Journal of Psychiatry titled “The Threat to Kill”.

The Macdonald triad is considered predictive of future criminal behaviour.

It should also be noted that Macdonald’s triad of sociopathic behaviours have often been correlated to early abusive up-brinings/witnesses to abusive/homocidal incidents.

If you are concerned about your child, please speak to a trained psychologist or psychologist.

If you would like to learn about more medical triads, please review my Waddell’s Triad of Trauma page.