David Masters, the Wiltshire coroner, was told that the vet, Dennis Archer, was being treated for severe depression before the killing early on 26 July.
No suicide note was left and there was no explanation for the deaths, he said in concluding the inquest in Devizes.
He found that Mr Archer, 71, struck his wife Margaret, 59, at least 12 times as she lay asleep in her bed at their home in Trowbridge.
Then the vet carefully washed his hands before climbing in his pyjamas through a skylight and sliding down the roof of the three-storey house to fall 40ft to his death on a gravel pathway.
The inquest was told that the couple's daughter, Sarah, 25, slept through the horror after returning home late from an evening out.
Before she left, her father had told her he felt he was 'losing his mind' - a statement he had made repeatedly in previous weeks as his condition worsened.
Miss Archer recalled in evidence how she was wakened by a telephone ringing. She went to answer it in her mother's room and found the blood-covered body. When she did answer the telephone it was the police who had been alerted by a passer-by to her father's body outside the house.
The inquest was told that the couple had been married for 29 years. Mr Archer had retired four years earlier from his Trowbridge practice, where he was known as a meticulous professional. But he developed depression and was being treated as an outpatient, was taking tablets and receiving counselling.
Miss Archer said her father worried 'immensely' over a number of events. On the night before the deaths he told her in his study that he was losing his mind and that he had 'had it'.
In summing-up, Mr Masters said that the Archers were a caring, normal and happy family.
He maintained that Mr Archer loved his wife and said: 'I do not know, but perhaps if he was going to take his own life he would not want to leave his wife behind. That is entirely speculative.'
He recorded a verdict of unlawful killing.