A jury returned a suicide verdict last week at the end of an inquest into the death of Kevin Olley, 26, a patient at Lister Hospital, Stevenage, in April 1998.
Mr Olley's case was one of three suicides at the hospital between January and June last year. Mr Olley, who had been diagnosed with schizophrenia in 1995, died after jumping from a 10th-floor window at the hospital.
According to the National Schizophrenia Fellowship, he suffered side- effects from his medication. Mr Olley's family claims he was denied a more expensive drug, Clozapine, on cost grounds.
Heather Lawrence, chief executive of North Herts trust, said Clozapine was prescribed if doctors were sure patients would comply with blood tests to monitor side-effects.