How would I answer a problem question involving diminished responsibility?

To answer a problem question involving murder and voluntary manslaughter, you first need to identify whether the defendant has committed both the actus reus and mens rea of murder (D must have caused the death of V and have malice aforethought). There are three partial defences to murder reducing it to voluntary manslaughter, however usually in problem questions you will only be able to identify two of them as a suicide pact rarely comes up - but it is still important to know what it is. Diminished responsibility is one of the other two main partial defences. When reading though a problem question, indicators that I would look out for where (a) has D suffered an abnormality of mental functioning, and (b) was this caused by a recognised medical condition, e.g. depression that a doctor has prescribed medication for. You would then need to apply s.2, Homicide Act 1957 (as amended by s.52, Coroners and Justice Act 2009) to determine whether D has the partial defence of diminished responsibility.