Abstract
ABSTRACT
Background: There is a huge controversy over failed applications of psychological principles and techniques to the trials of offenders who are mentally ill in Nigerian courts.
Aim: This paper is aimed at appraising the import of forensic psychology to the legal trials of mentally ill people.
Method: Nigeria laws are replete with Criminal Codes and Criminal Procedure Acts but there are numerous failed cases of insanity defences in Nigeria. The research technique of content analysis of insanity defences in Nigeria shows that there is a missing link.
Results: That broken link is the application of forensic psychology using a battery of standardized instruments, validated and culture free,
handled by unbiased and incorruptible forensic experts.
Conclusion: it was concluded that expert psychiatric testimony can play a significant role in the ultimate verdict, in insanity trials in Nigeria. This finding was explained with the classical positivist school by Lombroso. This author suggested that this broken link be fixed by the Courts deliberately involving forensic experts and their reports in passing judgments.

Key words: Keywords: Nigeria; Defence; Insanity; Law Courts; Psychiatry