text: Matthew Daley, 35, killed Donald Lock, on the A24 in Findon, near Worthing, last July after the 79-year-old ran into the back of his vehicle.
  Daley had admitted stabbing Mr Lock to death, claiming diminished responsibility.
  Lewes Crown Court heard Daley suffered from chronic mental health problems.
  The judge, Mr Justice Singh, adjourned the case for sentencing on 8 July.
  Mr Lock's family said the manslaughter verdict brought to a close the "most horrific 10 months of our lives and brings some sort of justice for Dad".
  However, they blamed the NHS for his death.
  "This verdict effectively provides the Daley family with what they have wanted for the last few years, their son in a safe place away from harm and being treated correctly," the family said in a statement.
  "For them they can still visit their son, hug him and talk to him and enjoy aspects of his life with him albeit constrained at the same time.
  "For us all we can do is cling on to the wonderful memories of Dad.
  "As a consequence of the failings of the NHS and this verdict, it is clear that Dad would still be here today if they had done their job properly."
  During the trial, jurors were told Daley's mother pleaded with mental health experts to have her son sectioned.
  She told the court, that the day she heard Mr Lock was killed was "the day that all your nightmares came true".
  Daley was charged with murder, but never denied killing Mr Lock.
  During police interview, he told detectives how he had used a knife to fatally stab Mr Lock, and while in prison awaiting trial he wrote and addressed a letter to the BBC in London, about what had happened on 16 July.
  The letter was seized before it was posted and was used as evidence.
  The great-grandfather, who had recently been given the all-clear from prostate cancer, was returning from a cycle meeting when his car crashed into the back of Daley's Ford Fusion.
  He and his wife Maureen had recently celebrated 55 years of marriage, and had two children.
  Chief executive of Sussex Partnership NHS Foundation Trust Colm Donaghy said they "got things wrong".
  "On behalf of the trust, I apologise unreservedly because the care we provided to Matthew Daley should have been better. I also want to offer my sincere condolences to the family of Don Lock and everyone else affected by this tragic, devastating incident."
  He said it was clear they should have reviewed the diagnosis, looked at other ways of providing treatment and "listened to his family" more closely.
  "We got things wrong. But I do not believe that any of our staff acted in a way which was deliberately negligent or designed to cause harm."
  Det Ch Insp Paul Rymarz, of Sussex Police, said Mr Lock's killing was a "tragic case" and had changed the lives of both families forever.
target: A man who stabbed a retired solicitor 39 times after a crash between their cars has been cleared of murder but convicted of his manslaughter.