Lady Gabriella Kingston has warned about the "side effects" of antidepressants as a coroner ruled her husband took his own life.
Thomas Kingston, who married the daughter of Prince and Princess Michael of Kent at Windsor Castle in 2019, died from a "severe traumatic wound to the head" at his parents' home in the Cotswolds on 25 February this year.
A gun was found next to his body.
Lady Gabriella cried while she sat in Gloucestershire Coroner's Court as a statement was read out on her behalf.
She said her husband had "seemed normal" in his final weeks and that she believed he had an "adverse reaction" to pills he had been taking.
Mr Kingston, a 45-year-old financier, had initially been given sertraline, a drug used to treat depression, and the sleeping tablet zopiclone by a GP at the Royal Mews Surgery, the inquest into his death heard on Tuesday.
The GP practice is based at Buckingham Palace and is used by royal household staff.
Stress at work
Mr Kingston had visited the practice after complaining of trouble sleeping due to stress at work, the inquest at Gloucestershire Coroner's Court heard.
He later returned to the surgery and said the drugs were not making him feel better before the doctor moved him from sertraline to citalopram - a similar drug,
In the days leading up to his death, Mr Kingston had stopped taking medication, and toxicology tests showed caffeine and small amounts of zopiclone in his system.
In a statement read out by Katy Skerrett, senior coroner for Gloucestershire, Lady Gabriella, 43, said: "[Work] was certainly a challenge for him over the years but I highly doubt it would have led him to take his own life, and it seemed much improved.
"If anything had been troubling him, I'm positive that he would have shared that he was struggling severely.
"The fact that he took his life at the home of his beloved parents suggests the decision was the result of a sudden impulse."
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'Adverse reaction to the pills'
She continued: "The lack of any evidence of inclination, it seems highly likely to me that he had an adverse reaction to the pills that led him to take his life.
"I believe anyone taking pills such as these need to be made more aware of the side effects to prevent any future deaths.
"If this could happen to Tom, this could happen to anyone."
Lady Gabriella said her husband had "seemed normal" in his final weeks, apart from early in the day after previously taking zopiclone, which she said made him seem "almost hungover".
In her statement, she described their marriage as "deeply loving and trusting" and said he had never expressed any suicidal thoughts to her or others.
Dad broke down in tears
Recording a narrative conclusion, Ms Skerrett said: "Mr Kingston took his own life using a shotgun which caused a severe traumatic wound to the head.
"The evidence of his wife, family and business partner all supports his lack of suicidal intent.
"He was suffering adverse effects of medication he had recently been prescribed."
She said she intended to draft a prevention of future deaths report, which would be sent to medical bodies.
Mr Kingston's father, William Martin Kingston, broke down in tears as he described finding his son in the locked bathroom of a detached annexe, having used a crowbar to break down the door.
He told the coroner that leading up to his son's death there did not appear to have been any searches for suicide, and no will or note was left, describing the method as "very ragged" which was simply "out of character".
Dr David Healy, a psychiatric medical expert who gave evidence to the hearing, said zopiclone could also cause anxiety, while sertraline and citalopram were both selective serotonin reuptake inhibitors (SSRIs), and essentially the same.
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'Guidelines and labels not clear enough'
Dr Healy said Mr Kingston's complaints that sertraline was continuing to make him anxious was a sign SSRIs "did not suit him", and he should not have been prescribed the same thing again.
He said the guidelines and labels for SSRIs were not clear enough about going on the drugs in the first place, or what the effect could be when moving from one to another.
"We need a much more explicit statement saying that these drugs can cause people to commit suicide who wouldn't have otherwise," he said.
Addressing the coroner, Martin Porter, counsel for the family, said: "The family don't blame [his GP], she was acting as good doctors do.
"But the question is whether there is sufficient advice to doctors on SSRIs."
Following Mr Kingston's death, the King and Queen sent their "heartfelt thoughts and prayers" to both families.
Prince Michael was a first cousin of Queen Elizabeth II.
Anyone feeling emotionally distressed or suicidal can call Samaritans for help on 116 123 or email jo@samaritans.org in the UK. In the US, call the Samaritans branch in your area or 1 (800) 273-TALK
(c) Sky News 2024: Lady Gabriella Kingston warns about 'side effects' of antidepressants after husband took h