I've copied part of some info on the Denbigh Hospital but I don't think that you will be able to access them due to the 100 year rule
The North Wales Hospital, Denbigh
The North Wales Hospital’s records are held by Denbighshire Archives Service. The collection is one of the most comprehensive examples of asylum records in the country. The hospital was known by various names during its existence- The North Wales Lunatic Asylum, The North Wales Counties Lunatic Asylum, The North Wales Counties Mental Hospital and The North Wales Mental Hospital.
The collection includes administrative records such as minutes and annual reports plus a fantastic collection patient records, from 1848 when the hospital opened and until the establishment of the NHS in 1948, and which have been used to research the care and treatment of patients and attitudes to mental illness.
Included in the patient records are a large number of reception orders which are bundled in chronological sequence. Reception orders provide evidence that the patient was ‘certified insane’ and include details of the patient’s behaviour prior to admission. Certification required the signature of two magistrates and the medical opinion of an approved doctor
Unfortunately, the catalogue for this collection is not available online, and can only be consulted in our office. These records are free to view at our office, however records which were created during the last 100 years are closed due to NHS patient confidentiality regulations. We are currently working with volunteers to create a comprehensive index of reception orders to make searching the 16,000 + records much easier for researchers.