A 17-year-old boy was found dead at a psychiatric unit in Bournemouth, a coroner has heard.
Henry Vickery, from Gillingham, was discovered hanged at Pebble Lodge in Alumhurst Road, Alum Chine, on 12 February, his inquest was told.
Staff checked on him at midnight and then at 01:00 GMT when he was found dead in a bathroom, it was heard.
The NHS has commissioned "an independent expert investigation" into his death.
Pebble Lodge is a four-bed adolescent inpatient unit offering treatment and assessment for young people with mental health problems, according to its website.
Colin Hicks, director of mental health at Dorset HealthCare, said: "Henry's unexpected and sudden death is a tragedy.
"This is a devastating loss for his family and friends and our thoughts are with them at this very difficult time. Everyone who was involved in Henry's care is deeply saddened by his death."
The inquest was adjourned for a pre-inquest review due to be held in Bournemouth on 26 September.