In A Murderess’s Tale, Theodore Dalrymple describes the English legal system’s concept of diminished responsibility, which leads to leniency in the case of a personality disorder — “or what used to be called a bad character”:
The use of personality disorder in such cases seems to me to be little else than a thin or even frivolous pretext for leniency, for if the argument were taken seriously it would lead to more severe punishment rather than less. If a man kills as a result of a momentary but understandable lapse, in unusual circumstances, he is guilty of murder but is unlikely to kill again; if a man kills because his character is deficient, and it is therefore the kind of thing he does, he is guilty of manslaughter but, ex hypothesi, is likely to do it again.
Dalrymple has some terrible stories to tell:
Not long ago, I testified in a case in which personality disorder served as an illogical pretext for leniency. A woman in her early forties, an alcoholic, had married another alcoholic and had a child by him. The father subsequently gave up drinking, separated from his wife — who continued to drink — and came to the conclusion that she was not a suitable mother for his child. He was in the process of applying for custody.By now, the child was two years old. One day, the mother — probably drunk — dissolved the contents of her antidepressant capsules in some cough medicine and injected the solution into the child?s mouth with a syringe. The child died as a result.