A man who was found hanged had suffered delusions of working with the SAS and the military, an inquest heard.
A hearing into the death of Thomas Rossington began at Norfolk Coroner's Court on May 19.
Mr Rossington was found dead at his parent's address in Cawston, near Aylsham, on November 21 last year.
Mr Rossington was born in Lincoln and had lived at his own house but for the final months of his life he was living with his parents.
His medical cause of death was given as hanging.
A statement from his mother, Frances Rossington, was read out, in which she said: "Tom had been struggling with his physical and mental health for a number of years.
"Over the past couple of years, especially with the Covid problem, Tom became more isolated."
The hearing heard Mr Rossington had been sectioned three times under the Mental Health Act in the months before he died and he had been admitted to several psychiatric institutions, including at Hellesdon and Ipswich.
In the statement, Mrs Rossington claimed that her son had suffered the effects of being poisoned by 13 heavy metals, which he was exposed to when they lived near the Bacton Gas Terminal when he was young.
But Yvonne Blake, the area coroner for Norfolk, said at the start of the hearing: "While I accept from the outset that you believe Thomas's problems were due to heavy metal poisoning ... it's not backed up by any evidence in the UK."
The inquest heard Mr Rossington had taken a prescription medication given to him by his girlfriend. The court was told he had suffered from delusions, including of working with the SAS and military, and Japanese and British embassies.
Mrs Rossington's statement said he had suffered from "dips" or mental health episodes which saw him being sick, having uncontrolled shaking in his leg and night terrors, losing his speech and having "complete brain fog".
She said he had a "lifetime of suffering" through no fault of his own.
There is still more evidence to be heard so a conclusion into Mr Rossington's death was not reached. The hearing will continue at a later date but this has not yet been set by the coroner's office.
*If you need help and support, call NHS 111 and select option 2 or the Samaritans on 116 123. Both services are available 24 hours, 7 days a week. You can also download the Stay Alive app on Apple & Android.
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