Henry Cockburn was diagnosed with schizophrenia in 2002 at the age of 20. Before that he was a heavy cannabis user.
His father, Patrick Cockburn, has long wondered whether the two were linked and spent months speaking to the world's leading experts in the field. In a four-part series prompted by his son's condition, he will examine the medical evidence linking sustained cannabis use with schizophrenia, before going on to look at the way the mentally ill have been let down by the health service and stigmatised by public opinion, and concluding on Thursday with his manifesto for a more humane and effective system – accompanied each day by Henry's account of his journey from pyschosis to a normal life.
For cannabis smokers diagnosed years later with schizophrenia the outcome is a lifetime battling with psychosis, including symptoms such as paranoid delusions, hostile voices and unexplained waves of terror and guilt. Many sufferers end up isolated, jobless, impoverished and with their lives ruined.
Pro- and anti-cannabis campaigners have furiously disputed the dangers of taking cannabis. Proponents of decriminalisation claim it is no more risky to health than junk food. But doctors and nurses treating the mentally ill in Britain have long noticed that a very high proportion of their patients are serious users of the drug, often starting to take it at a young age. Dr Humphrey Needham-Bennett, medical director and consultant psychiatrist of Cygnet Hospital, Godden Green in London, says that among his patients "cannabis use is so common that I assume that people use or used it. It's quite surprising when people say 'no, I don't use drugs'."
A psychiatrist leading an Early Intervention in Psychosis team in a large inner city area, who did not want to be identified, likewise says "it was not fashionable to say so in the 1990s, but any practising mental health professional would agree that if you smoked a lot of cannabis, particularly in your teenage years, there is a risk of psychosis. Studies coming out over the last five years have confirmed this."