THE psychiatrist of murder accused Joanne Hussey said it is rare for someone to act on voices in their head and kill.
Dr James Berry says he can only recall one case of someone with a depressive illness carrying out the actions of imaginary voices.
He also agreed it was puzzling that Hussey asked a police cell officer what would happen if she were to say she heard voices in her head telling her to kill.
Hussey, a mother-of-one, is accused of killing her grandmother, Annie Garbutt, of The Clough, Mirfield, on May 7, 2007.
She is alleged to have murdered Mrs Garbutt with a garden spade.
She denies murder, but admits manslaughter on the grounds of diminished responsibility.
Prison psychiatrist Dr Berry, giving evidence in the trial at Leeds Crown Court, said: “Depression is a very common illness, few people suffer it to a very severe extent.
“Very few people go on to act on abnormal beliefs in a violent way. It is rare.
“The assault would have been prolonged and involved extreme levels of violence.
“Her historical pattern of violence, as I understand it, has been due to her sudden loss of control.
“I would certainly expect someone suffering from a severe depressive illness to show a decline or function in the way they present.”
He agreed that Hussey was functioning normally before the killing, giving no signs of her state of mind to close family and friends or mental health workers.
The psychiatrist also said he had never heard of a case of someone offering money to friends to corroborate a story.
The jury heard that Hussey may have suffered alcohol amnesia on the night of the brutal killing.
But her account of how much alcohol she had consumed has varied since she was arrested on suspicion of her grandmother’s death.
She once claimed to have drunk half a bottle of vodka and around two thirds of a bottle of Baileys, which is the equivalent of around 19 pints of beer.
But during the hours of May 6 and 7, she was captured on CCTV camera driving to and from her Leeds home to Mirfield.
Dr Berry said: “I would certainly be sceptical about the amount of alcohol she says she had consumed.”
But Dr Berry said her account of hearing voices remained consistent.
He added: “There are no alarm bells ringing to say she was making it up.
“I have considerable experience of people telling me they are hearing voices and then it transpires that is not the case at all.
“But the description she has given doesn’t ring any alarm bells at all, it has remained consistent.”
The case continues.