A week-long trial at Stafford Crown Court has been told 70-year-old Richard Hall was stabbed more than 20 times by Moses Christensen, who was living rough in the days leading up to the killing.
Christensen, of Corser Street, Stourbridge, West Midlands, told police after the stabbing that he had carried it out "just for the sake of killing somebody", near the summit of Shropshire's Brown Clee Hill.
Jurors have heard evidence from three psychiatrists about the defendant's mental state at the time of the death on August 13 last year.
Coverage of the case:
Giving evidence by video-link last week, Home Office-approved pathologist Dr Brett Lockyer said Mr Hall had suffered 26 injuries, including a "horrific" wound to his hand and another which had penetrated his skull.
Forensic psychiatrist Dr Dinesh Maganty told the trial he believed the "significantly impaired" psychotic condition of Christensen was the only explanation for the killing.
Christensen opted not to give evidence to the jury.
Prosecutors allege the privately-educated 22-year-old was able to understand the nature of his conduct, formed rational judgments and killed Mr Hall "because that is exactly what he wanted to do".
Jurors have been told they must decide whether the unlawful killing of Mr Hall, who lived in Perton, South Staffordshire, was murder or manslaughter on the grounds of diminished responsibility.