Where fairness in medical care begins

He's possessed by demons.

My son, now 25, had been complaining of feeling possessed for the last 6 months or so. He would complain that he was hearing the voice of the devil, telling him to do some rather ghastly things. We thought it was a split-personality thing but my son insisted it was the voice of the devil.
 
At times his right arm would shoot up while we were having a meal. This is extremely inappropriate. He'd say that the devil made him do it. This would erupt in an argument because we would say 'don't be daft'. He finds that smoking cannabis occasionally gives him relief, from the voices. However, we looked on the internet and they say that's a bad thing to do, especially if people are hearing voices. I know that voices can mean schizophrenia, but it doesn't run in our family. My grandmother suffered with depression but that was about it. So, I'm thinking that it must be the cannabis that's causing this.
 
I took him to see my GP. He gave us some sleeping pills - zopiclone  - and said we should wait and see. The GP said that it could be demon possession and that schizophrenia was unlikely because it did not run in the family.
 
Last night he woke up in the night and began shouting. We rushed upstairs to find him in an agitated state muttering to himself and looking very strange. He looked at us in an 'evil' way. He'd never looked like this before. He took one of the pills and after about an hour calmed down.
 
Our family is very concerned because we're not sure if he's been treated right. Can you help.
 
Response:
  1. We try our best to avoid giving medical advice via this site.
  2. It's not certain that there is a medical mishap here, however we respond with some guidance to assist others who may be in similar situations in the future.
  3. There are worrying problms for your son's mental health.
  4. Cannabis is known to contribute or trigger voices and symptoms very similar to schizophrenia.
  5. Demon possession is not something we would entertain as a possibility.
  6. The term split-personality is not related to a diagnosis or condition we are aware of that seems relevant to your son's condition.
  7. If you can gently persuade your son not to use cannabis that may be helpful, but do not get into arguments about it.
  8. You need to decide based on the severity and duration of your son's apparent health problems, whether to seek a Mental Health Act assessment. You could and should request this in writing to your GP (and keep a copy of any correspondence).
  9. Your son could be at risk to himself or others, or his health could be seriously in danger - and as non-professional people you're unlikely to aware of the risks, without an assessment. The assessment could mean an offer of psychiatric admission, outpatient follow up, or  him being detained in hospital. In the UK a Crisis Response Team may be the first to respond.
  10. At some appropriate point you should consider expressing your dissatisfaction to the GP.
  11. You should also seek an assessment for your son my a consultant psychiatrist.