The binding legal principles established are: (1) Under s 18(4) of the Criminal Law (Codification and Reform) Act, the burden of proving mental disorder or defect at the time of commission of an offence rests on the accused on a balance of probabilities, not on the prosecution; (2) The law presumes all persons to be of sound mind until proven otherwise; (3) The relevant mental state for determining criminal liability is the accused's mental condition at the time of commission of the offence, not at any other time; (4) Rational conduct, coherent explanations for behavior, knowledge of right and wrong, and ability to recall events are inconsistent with a finding of mental disorder that would negate criminal liability; (5) Trial courts have a duty to properly investigate and consider all mitigating factors before imposing sentence, particularly where an unrepresented accused raises such factors; (6) Failure to adequately consider material mitigating factors, such as provocation through assault or possible intoxication, constitutes a misdirection in sentencing warranting appellate interference.