Alastair Campbell believes that the world of politics attracts a higher proportion of mentally unstable and psychologically challenged people than other walks of life. But unlike Campbell himself, few who have been close to the levers of power are willing to talk openly about their mental health.
He lived in the frontline of politics as Tony Blair's chief spokesman and strategist in 10 Downing Street. He was there through such tumultuous events as the Good Friday Agreement, the 9/11 attacks and the Iraq War, which mired him in the greatest controversy.
Campbell was one of the strategists credited with rebranding his party as 'New Labour' and making it electable again in the post-Thatcher period. But before, during and after this time at the heart of government, Campbell has suffered severe depression.
In his new book, Living Better, he explores how he dealt with what he terms "the demon inside me" - firstly through drink, then through manic "workaholism" and desire to be at the centre of things, and finally through more constructive psychological strategies. When we talked in recent days, Campbell said he had been through a difficult few months during the lockdown.
"I was very up and down. I started out really enjoying it, then I became manic, and then I had a big crash towards the end."
With age and experience, Campbell feels that he has developed effective ways of coping, but the struggle has rarely been easy since his life hit rock bottom in 1986, when he gave up drinking.
As a journalist for the now-defunct UK tabloid Today, Campbell had been on a wild drinking spree when he travelled to Scotland to interview the Labour leader Neil Kinnock. Campbell had what he has described as a "severe psychotic breakdown".
He dumped a hired car in the middle of Glasgow, and at one of Kinnock's events, he suddenly heard strange sounds and voices - bagpipe tunes, Abba, Elvis and people shouting. He ended up being arrested and hospitalised. "The psychiatrist who treated me then led me to the position where he was saying, do you think it might be an idea if you didn't drink. So, I didn't drink for 13 years."
In his book, he recalls how Vladimir Putin remarked at one meeting with him and Tony Blair that he wasn't touching the vodka and wines lined up as toasts. "He's not allowed - he's a thing-aholic," said Blair.
When Campbell was working for Blair in Downing Street, the administration was riven by the rivalry between Blair and the chancellor of the exchequer Gordon Brown.
This combustible mix of friendship and deep enmity left such a deep mark that at one stage Campbell's psychiatrist suggested that Blair and Brown should be part of a group therapy session. It never happened.
The administration divided into two factions - those surrounding Blair, and the Brownites. Campbell recalls that at low points, some of Brown's people would tell Blair to f*** off. But they could deal with one of Brown's more conciliatory supporters, Ed Miliband, who later became Labour leader. He became known as "the emissary from the Planet F***".
Depressive episodes continued to strike when Campbell was in government, and even on the night when Blair won power in 1997, he was overwhelmed by a feeling of dejection.
Remarkably, Campbell says that his paralysing depression only very rarely stopped him carrying out the vital functions of his job.
So how did he cope with the pressure? "My wife Fiona refers in an afterword to the book to advice given by [former Manchester United manager] Alex Ferguson that when you are under pressure, it is like looking into a tunnel.
"You only let into the tunnel those who need to be there for what you want to do. Fiona says she wasn't allowed into that tunnel at times."
Campbell says he parked his depression, so it didn't overwhelm him when he was doing his job. He says that when it did overwhelm him, he was often at home.
He came under most pressure over British involvement in the invasion of Iraq, and there was an accusation that he "sexed up" an intelligence dossier about Saddam Hussein's alleged weapons of mass destruction.
He resigned in the summer of 2003, but says he has been vindicated by a number of inquiries. The Chilcot inquiry published in 2016 concluded: "There is no evidence that intelligence was improperly included in the dossier."
Campbell admits that there were problems with the Iraq War. Asked what went wrong, he says: "It was the assumptions we made about the aftermath planning, particularly by the Americans. I can still justify the decisions that were made, but in terms of the aftermath, nobody can pretend that it went exactly as planned."
He says that it was after he left his job in Downing Street that he had one of the worst depressive episodes in his life. He feels he had kept depression at bay through a mix of will power and being constantly busy.
"I think I had a physical decompression - I almost found myself unravelling inside. I had a mini-explosion on Hampstead Heath and I started beating myself up. When you are doing that out in a public place with your partner, you know something is wrong."
It was then that he was persuaded to see the psychiatrist David Sturgeon, and he regards that as a turning point in his life. He says he has now found a better way of dealing with his depression. "I have got better at embracing it, and realising that that is what is I have to deal with," he says.
He takes the anti-depressant Sertraline, and has tried a wide range of techniques and mind exercises that are outlined in the book, including drawing up a gratitude list. He now drinks very little and places a strong emphasis on sleep, diet and exercise.
"I do circuits, I see a trainer a couple of days a week, I do boxing, swimming, cycling and running. When we were away in the summer, I cycled three or four hours a day - and I like to be in bed before 10."
He is still drawn irresistibly to politics. "My psychiatrist says part of my demon is my inability to resist being dragged into the centre of these political situations."
But he has learned that there are times when you should enjoy the silence and turn off the news. And of course that must be easier when your name is not featured at the top of the bulletin.
'Living Better' by Alastair Campbell, published by John Murray, is out now