Lady Hamilton wants to stop people being held in such institutions on the orders of just two people, backing campaigners' demands for forced detentions to be approved instead by a panel of experts.
She made the call as she recalled her experiences of the 2009 detention of her husband when he was suffering with dementia. He died in June 2010 at the age of 71.
Lady Hamilton said that her husband had been cared for at home until a psychiatrist suggested they go to hospital to check his medication.
She said she was led to believe it would be for a few days but found out that her husband had actually been sectioned for 28 days - something that "really upset" him.
"I could hear him calling for me: 'Kay', 'Kay'," she said. "I said, 'It's alright pet. You're here voluntarily, you can come home if you want to'.
"Then a voice behind said, 'No he can't. He's been sectioned for 28 days and he may not get out then'."
She recalled seeing him try to escape from a first-floor window on one occasion.
"He rushed out into my arms saying, 'home!' and then they had to pull him away from me," she said.
"I thought, if this can happen to the Duke of Hamilton, what chance has Joe Bloggs got?"
He was later discharged but Lady Hamilton said she believes the episode hastened his death.
She is now calling on the Scottish Parliament to examine changes to Scotland's Mental Health Act, which allows for a person's detention against their will if a doctor and a mental health officer agree that they suffer from a mental disorder.
"Please look at this Act and implement something to prevent this happening," she said.
Angus Douglas-Hamilton was born in London in 1938 and was the eldest son of the 14th Duke of Hamilton.
The duke held the role of Premier Peer of Scotland and was the Hereditary Keeper of the Palace of Holyroodhouse, the Queen's official residence in Scotland.
He could trace his ancestry back to Mary Queen of Scots and was custodian of the family's 14th-century seat, Lennoxlove House in East Lothian.
The Hamilton dukedom is the oldest in Scotland, dating back to the mid-17th century.
Dr Donald Lyons, chief executive of the Mental Welfare Commission, said: "In general, Scotland's mental health legislation is regarded as a leader in good, ethical approaches to compulsory treatment for mental health problems.
"But practice can always improve and it's important to learn from people's experiences.
"We have given advice and made recommendations about making sure that people being detained and their carers are given a good explanation as to the reasons so they can challenge them."