Officials at a psychiatric hospital in West Australia are investigating how a healthy man, mistaken as a runaway mental patient who had previously escaped from the mental health clinic, ended up being forcefully detained at the facility and injected with anti-psychotic drugs that made him so sick he had to be hospitalized.

The unidentified man was picked up by police on December 16 and detained at Graylands Hospital, in Perth, Australia because he matched the description of an involuntary patient who had run away from the clinic two days earlier, according to news.com.au.

Staff at the mental hospital did not realize they had the wrong man and mistook the man for his escapee doppelganger.

It wasn't until after the staff had injected the man with a dose of a strong anti-schizophrenia drug called Clozapine, a drug usually administered only when other antipsychotics don't work, that they found out that they had the wrong man.

The powerful injection produced a serious adverse reaction in the man, leading to him needing overnight treatment at the nearby Sir Charles Gairdner Hospital.

It was unclear when the mental health clinic staff realized their mistake, but WA Mental Health Minister Helen Morton apologized for the 'dreadful mistake' and authorities are now investigating the incident.

"I am very sorry for the distress and hurt that the misidentified man has endured," said Mental Health Minister Helen Morton, according to The West Australian. "I find it hard to imagine that if proper processes were followed, there is any excuse for such a terrible mistake to be made. I will await the outcome of the clinical review, however people must be held accountable for this dreadful mistake and ensure it never happens again."

The real runaway mentally ill patient had returned to the psychiatric hospital by himself that same day.

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