Diminished responsibility and insanity are not the same thing see R v Rose (1961) (Privy Council). In R v Seers, the accused suffered from chronic depression and stabbed his wife. The accused was charged with murder and at the trial the judge directed the jury that they should only find the accused guilty of manslaughter if his depression bordered on insanity. The accused appealed on the grounds that the judge had erred in his direction and the court in line with R v Byrne (1960) held that in order for the defense of diminished responsibility to be raised the accused had to establish abnormality of mind as per S.2 of the Homicide Act (1957). The accused was found to be guilty of manslaughter.
It is normally a good idea to produce medical evidence when raising the defense of diminished responsibility and while the jury may refuse to take into account or consider the medical evidence, they can do so if they find that the medical evidence has been tampered with see Walton v The Queen (1978) (Privy Council) or if the interests of the public are better served by a conviction see R v Sutcliffe (1981), they would normally take into account the medical evidence that has been presented.
In R v Reynolds 1988 the accused was suffering from post-natal depression, after she’d had a baby without the knowledge of her family and during an argument with her mother, she clubbed her mother to death with a hammer. At the trial, the accused raised the defense of diminished responsibility and the defense produced medical evidence to support her claim. The accused was convicted of manslaughter instead of murder and her defense was successful.
R v Tandy (1989) once again supports the presumption that excessive drinking or alcoholism in itself is not sufficient to raise the defense of diminished responsibility in a murder trial unless the excessive drinking has induced an abnormality of mind within the meaning of S. 2 of the Homicide Act (1957).
In R v Tandy (1989) the accused strangled her 11-year-old daughter to death after she complained to the accused that she had been sexually abused by her stepfather. The accused had been drinking heavily just prior to the incident and at the time of the incident she was very drunk. The accused was tried and convicted for murder. The accused appealed but the appeal was dismissed.
In assessing whether the defense of diminished responsibility can be successfully raised there are two principles to be considered. Firstly, if there are no other factors to be considered, unequivocal and un-contradictory medical evidence favorable to the accused should be accepted and the direction to the jury should be as such and secondly when there are other factors to be considered the medical evidence though unequivocal and un-contradictory should be considered in light of those factors or those circumstances as per R v Sanders (1991).
In R v Sanders (1991) the accused killed his wife with a hammer because she was having an affair with another man. The accused was a diabetic and because of his illness had lost sight in one eye which caused him to sink into depression. The accused was tried and convicted and the accused appealed on the grounds of diminished responsibility. The appeal was dismissed and the accused was held to be guilty of murder based on the principles stated above.
In R v Egans (1992) we once again examine if killing a person while in a state of drunkenness will allow the accused to raise the defense of diminished responsibility. The accused entered a home with the intention to rob and stumbled across an elderly widow. He attacked her and she died as a result of the injuries sustained. He had been drinking heavily prior to committing the act and the accused suffered from an inherent mental disability that was similar to a development disorder.
The court applied the test in R v Gittens (1984) and decided that the question that was to be asked is if the mental illness was sufficient to constitute an abnormality of the mind without taking into account the fact that the defendant had been drinking and would that abnormality of the mind have driven the accused to kill without the influence of alcohol? It was decided that the abnormality of the mind would not have lead the defendant to kill and the fact that he was drunk at the time was not sufficient to raise the defense of diminished responsibility.