What was Harold Shipman's psychological state?

Just after 6am yesterday, Harold Shipman, described as a man addicted to murder by the judge inquiring into his 23-year killing spree, wound one end of a prison sheet round his neck and the other round the bars of his cell and took his own life on the eve of his 58th birthday. Shipman, Britain's most prolific serial killer, will go to his grave having apparently left no explanation as to why he murdered 215 of his patients. His "obnoxious" arrogance and rudeness to prison staff had quickly led him into trouble.