I used to do some extremely odd things during manic episodes, when you feel euphoric, uninhibited, full of energy and talk non-stop. Once, I went charging back to my school two years after leaving it. I went bursting into classrooms, interrupting lessons and causing havoc.

I barged my way into a physics lesson and started pontificating to the class, as my old physics teacher looked on in horror. I did the same thing at a management consultancy where I worked briefly, storming in there and talking excitedly to everyone, a crowd gathering around me. Although I wasn't remotely religious, when at my most ill I thought I was on some kind of mission from God and was going to usher in the Second Coming. I remember seeing God's face in anything and everything.

It has been suggested that having a celebrity's ultra-outgoing personality might dispose someone to bipolar illness. At least one in 100 people has bipolar disorder. Most are ordinary, everyday people.

If you are mildly manic you bubble over with energy and creative ideas. If you are creative already, the ideas and imagination will overflow. I remember spouting poetry when wandering around Edinburgh Festival while manic. If I had had a gift for poetry, it might have been an incredibly productive phase for me.

I was first diagnosed as bipolar at 19, but the symptoms started when I was much younger. I went to a grammar school in Amersham, Buckinghamshire, and was a high achiever academically, as well as being very sporty and popular. But I was a real worrier, and always have been. In my early teens, if I got upset about something it would go on for several days. Later, I started having regular and increasingly severe mood swings.

The illness got more and more extreme. The highs were getting worse and I was losing all sense of reality. Instead of just seeming lively and chatty I was talking constantly – my speech became so fast I ceased to make any sense at all. I also did really odd things such as taking photos of people in the pub, or stealing a pint of milk from behind the bar and drinking it.

One day my mum called the GP, who recognised I was so ill I needed to be treated in hospital. When I was high the GP persuaded me to go to hospital with her – once I was there, I was trapped. They could see I was severely ill and detained me under section. That was very traumatic. It dawned on me, even though I had nearly lost touch with reality, that I was going to be held there. I was desperate to leave and felt betrayed by my family. I got into a stand-off with a bevy of burly psychiatric nurses, who surrounded me and had no intention of letting me make a break for the exit.

In the end I was shut in a room as they held the door shut. Eventually they stormed in, pinned me down and forcibly sedated me. The next few days were a blur of heavy tranquillisers that only took the edge off my mania. I still stalked the ward thinking I was either Jesus Christ or the Dalai Lama, and painted the "evil eye" in a manic delirium during art therapy.

It took another decade, and a suicide attempt, before I got proper treatment. By that time I had received a postgraduate degree in journalism, worked in various news agencies and a government press office, and met my wife, Suzanne. She is an amazing, long-suffering woman who stuck by me during my illness. We are blessed with two wonderful children.

For years my doctors failed to see I was depressed. I was angry with my psychiatrist for not being proactive enough about my treatment; he could have saved me from all those wasted years. But since then they have experimented with my medication. I'm now on the anti-psychotic quetiapine, the anti-epileptic sodium valproate and an anti-depressant, which together seem to work very well.

I still have occasional mood swings, but they're nowhere near as severe. I recently became a trustee of the user-led charity Stand to Reason, which challenges prejudice towards people with mental illnesses. Recovering has made me want to improve the lot of people like me.

The writer works for Shift, a campaign against stigmatising mental illness