Abstract
Background: Expert psychiatric testimony may be relevant in certain instances of homicide especially murder. However, the exposure of most psychiatric trainees may be inadequate in relation to the range of psychological defences available to an offender accused of homicide.
Aim: To describe the psychiatric and psychological defences to murder available within the Nigerian legal context as well as review cases of witchcraft defence within the same jurisdiction.
Method: Review of extant laws in relation to murder using the Criminal Code, the Penal Code and the Criminal
Procedure Act where applicable. Cited cases were presented from standard Law Reports.
Results: The criminal defences in Nigerian courts which possess psychological and psychiatric
modulation notably include the Insanity Plea, “Witchcraft" defence, and the defence of intoxication. Self-defence, Defence of Provocation, and “Doli
In capax” also demonstrate indirect psychological or psychiatric
underpinnings. The “Witchcraft" defence appears to be the most tenuous and least justifiable of the pleas highlighted.
Conclusion: A fairly wide range of psychological and psychiatric defences are proffered in Nigerian courts in the defence of criminal acts, including murder. Some require expert testimony where insanity and related issues are raised. Thus, mental health experts practicing in Nigerian jurisdictions have both an educative role and a moral responsibility to provide evidence-based testimony during court proceedings.

Key words: Key words: expert testimony, psychiatric, psychological, defence, insanity.