Founded by the O'Kane family, Hawthorne was built on land that served as a synapse between the physical world and a reservoir of evil, meaning that unusual deaths occurred in the area dating back to the 13th century. The O'Kanes served as its directors from its inception.
On 13 August, 1945, the director of the clinic, Eustace O'Kane, was murdered at Hawthorne by his son Daniel, as were his wife and daughters. Daniel was found insane and consigned to various asylums whilst Jeremiah O'Kane took over the clinic before retiring and handing the directorship to Colin Dove.
Dr Dove was a sensitive and was aware of Hawthorne's history. He planned to unleash the reservoir of evil at perihelion in 1994 out of scientific and personal curiosity, a plan to which an ageing Dr O'Kane was also party to. Dr Dove arranged for Daniel to be brought back to Hawthorne under the name of "Patient Zero". This had the effect of attracting Daniel's son Peter Russell to the clinic. When the Care in the Community scheme meant that Hawthorne was to be closed, Russell kept it open.
There were eight deaths following Daniel's transfer to Hawthorne, which attracted the attention of P.R.O.B.E.'s Liz Shaw and Louise Bayliss. Following the death of William Bruffin, Dr Dove was arrested on suspicion of his murder before being killed himself. Liz and Russell discovered the identity of Patient Zero and Liz realised that the reservoir needed Russell and Daniel together at perihelion to break free. In a moment of clarity, Daniel jumped in front of a possessed Russell's knife.
Eustace O'Kane was director of the clinic before his murder by a possessed Daniel, after which his other son Dr Jeremiah O'Kane took over. Following his retirement to a house on the clinic grounds, Dr Colin Dove became director. Ultimately Peter Russell took charge after stepping in to keep the hospital open, but he kept a hands-off approach whilst Dr Dove was still there. Dove was killed by Daniel.
Patients at the hospital included Clegg (who was schizophrenic) and Daniel O'Kane ("Patient Zero") and Patient One (who were both sensitives affected by the reservoir of evil). (HOMEVID: The Zero Imperative)