Non Compus Mentis

Non Compus Mentis

Literal Meaning

 Not of sound mind and understanding.


This phrase was first used in thirteenth-century English law. In medieval and early modern Britain, the term Non compos mentis was often related to religious or mysterious phenomena such as diabolical influence. From the seventeenth century, the condition was increasingly viewed as a mental illness, also described as insanity or madness.


In English law, Non compos mentis was a juristic term to describe a person’s action as not motivated by reason, but being influenced by some false image or mental impression.[2]Non compos mentis and felo de se (the Latin word for “self-murder”) presented two different verdicts in the case of a suicide. In the finding of a jury, the deceased who was stigmatized felo de se would be excluded from burial in consecrated ground and would forfeit their estate to the Crown, while these penalties would not apply to the deceased affirmed non compos mentis, i.e. deemed to be insane.


The state of mind of self-killers at the time they committed their fatal deed was crucial. To be judged guilty of “self-murder”, one had to be sane. Men and women who killed themselves when they were mad or otherwise mentally incompetent were considered innocent

Cases referred

The medieval theologian Thomas Aquinas extended Augustine‘s arguments against suicide and added the new interpretation of “violation of natural law to it. Most western European governments began to promulgate laws to confiscate some of a suicide’s property.

However, attitudes to suicide changed profoundly after 1660, following the English Revolution. After the civil war, political and social changes, judicial and ecclesiastical severity gave way to official leniency for most people who died by suicide. Non compos mentis verdicts increased greatly, and felo de se verdicts became as rare as non compos mentishad been two centuries earlier.

Edited by Vigneshwar Ramasubramania

Approved & Published – Sakshi Raje