The sister of a caretaker who hanged himself in a school gym told his inquest she blamed anti-depressants for contributing to his suicide.
Gordon Briggs, 58, was found hanging by a climbing rope at Townsend School in Bournemouth, Dorset, on 29 March 2008.
The special measures school is to close in July which also contributed to Mr Briggs' depression, the inquest heard.
But his sister said his mood changed after his medication was altered. A suicide verdict was recorded.
Linda Aldham told the inquest on Wednesday her brother became restless and heard voices in his head telling him to commit suicide, shortly after he started taking the anti-depressant citalopram.
She said: "Within the space of three weeks my brother took three overdoses and then he hanged himself."
His wife Yvonne also said he would sleep all day when he was not working and in the weeks leading up to his death he had been signed off work with stress.
Ms Aldham started researching the drug on the internet and found side effects which matched her brother's.
But Mr Briggs' GP Nigel Irwin said he had taken the drug once before and that it was recommended by the National Institute for Clinical Excellence (NICE).
He prescribed 10mg, half the normal dose, before increasing it to 20mg following Mr Briggs' second overdose.
The inquest heard despite research there was no evidence linking citalopram with suicide.
Mr Briggs was also worried about the threat of closure and the fact he would lose the house that went with his job, the inquest heard.
Pc Joy Wright, of Dorset police, said in a statement: "Mr Briggs had been suffering from depression and possibly the imminent closure of the school had contributed to his condition."
On Tuesday, councillors voted to close the school at the end of this term citing poor Ofsted reports, low test results, failing pupil numbers, lack of value for money and difficulty in recruiting staff.