Scott Morrison says he took medication for anxiety while he was ...

Former prime minister Scott Morrison has revealed he was treated with medication for anxiety while serving as the nation's leader. 

Mr Morrison shared an extract of his forthcoming book to The Australian, where he wrote that he experienced "debilitating and agonising" anxiety during much of his time as prime minister, and that he would have become seriously depressed without medication. 

Beyond Blue estimates one in four Australians are affected by anxiety, and politicians are not immune, but mental health issues are still rarely made public in federal politics. 

In a book Mr Morrison says explores how faith intersected with his time as leader, he wrote that the toll of the job had worn on him, and his waves of anxiety had become acute. 

"My doctor was amazed I had lasted as long as I had before seeking help," Mr Morrison wrote. 

"Without this help, serious depression would have manifested. What impacted me was the combination of pure physical exhaustion with the unrelenting and callous brutality of politics and media attacks.

"As a politician, I know this goes with the territory. That’s not a complaint or even an accusation. It’s just reality. Politicians are not made of stone, yet they’re often treated as though they are, including by each other."

Mr Morrison told the ABC his Christian faith had also served as a major aid for him.

"The meds were helpful, but faith for me has always been the major ingredient," Mr Morrison said.

In a post on social media, Mr Morrison said he was sharing his experiences to normalise a common issue for many Australians.

He also told the ABC he wanted to make clear that politicians can have mental health issues and still perform their jobs.

"Because I sought help I was fully functional. [It is] important that people understand that this doesn't have to hold you back. I went on to land AUKUS in the midst of this," Mr Morrison said.

A few politicians have disclosed their own mental health struggles after leaving politics, including another former prime minister, Malcolm Turnbull, who said he had suicidal thoughts the first time he was ousted as Liberal leader.

Former trade minister Andrew Robb made an even rarer disclosure of his own mental health issues while still serving as an MP, and said at the time while many colleagues were supportive he also faced stigma and doubt from others.

Speaking on Channel Nine, former treasurer Wayne Swan said politicians should be open about mental health.

"It's relentless, it's 24/7. They're high-pressure jobs and there is a risk to health with that pressure," Mr Swan said.

"There are many people who have been in that position [like Mr Morrison], and the more we talk about it the better, I think leaders need understanding and people need to understand that leaders can be under pressure."