Alastair: I suffered severe depression at Downing Street

I had a pretty spectacular nervous breakdown when I was a journalist at the Daily Mirror. I was poached by Eddy Shah's Today newspaper when it launched. It was a disaster. I was over-promoted, I hit the bottle pretty hard, went completely manic and cracked up.

On the day it happened, I was doing a piece on Neil Kinnock in Scotland. It was like this piece of glass cracking in slow motion into thousands of pieces inside my head. I was struggling to hold it together but the harder I tried, the more the glass cracked, and I ended up with an explosion of sounds, memories and madness reverberating through my mind.

I got detached from the main press pack and was picked up by the police because I was behaving oddly, putting all my possessions into a little pile in the foyer of a building I'd wandered into.

I was in a psychiatric hospital for a few days, heavily drugged. I was treated for depression and was on medication for a few months. There are not many things as deadening as real depression, when you feel unable to move a muscle and you're incapable of getting out of bed, or speaking or thinking, or doing anything, and you can't see a way forward. But I got through it eventually.

I was really lucky. Fiona, my partner, was incredibly supportive. Richard Stott, who was editor at the Mirror, took me back. He gave me a chance and that was a huge thing for me, an act of support people often don't get when they become ill.

When Tony Blair asked me to work for him in 1994, I said "You do know about my breakdown don't you? You do know I still get depression."

He said "I'm not worried if you're not worried." I said "What if I'm worried?" He said "I'm still not worried." I think that's an important signal for us to take on board - if a Prime Minister can take that attitude, we all can.

I suffered severe bouts of depression during my time at Downing Street.

At times I was so depressed I'd wake up and couldn't open my eyes, I couldn't find the energy to brush my teeth. The phone would ring and I'd stare at it endlessly, unable to answer it.

I've wanted to be open about my mental health problems, because I know from my own experience how it helps to know there are other people out there who have been to the brink and come back again.

If it happened to me, it can happen to you - it will almost certainly happen to a friend, colleague or relative. Help encourage more openness about mental illness and challenge the stigma - don't reinforce it.