Voice judge will.i.am telthe hyperactivity disorder he grew up with was a blessing not a curse – as it drove him on to become a global superstar

He is one of the longest-serving judges on TV talent show The Voice and a seven-time Grammy-winning pop star – propelled to superstardom, he says, by the hyperactivity disorder he suffered as a child.

And today in an exclusive Mail on Sunday interview, will.i.am criticises parents who choose to give their children with the condition 'potential destroying' drugs.

Speaking exclusively to Event magazine, he tells of his relief that his mother never made him take Ritalin, the drug commonly prescribed for ADHD. He says: 'It's not the kids who are the problem, it's the lazy parents and lazy teachers who want kids to take Ritalin.

'You don't need medication, you need patience with kids who have ADHD. It's destroying so much potential and no one gives a damn.'

Born William James Adams, the 43-year-old, a founding member of chart-topping band The Black Eyed Peas, believes his ADHD gave him creativity which he poured into music. 'I was fine because I had a patient mother and some patient teachers,' he says, 'but it makes me furious that you get a kid who has this creative energy, who is powering off the walls and people can't be bothered to deal with energy. They just want to medicate it away.

'You'll get a teacher who says to a parent, 'Your child is not like the rest of the kids. He talks all the time, he runs about, he's into everything but there is a pill you can give him to slow him down.' Why? Why not encourage that energy, direct it, have the patience to develop and harness it?

He adds: 'My mum couldn't have afforded Ritalin because we had no money, but she also wasn't afraid to say, 'No. Leave my kid be.'

Will.i.never! The Voice's hyperactive star will.i.am gives his most outspoken interview ever

Voice judge will.i.am tells Event the hyperactivity disorder he grew up with was a blessing not a curse – as it drove him on to become a global superstar. Which is why he's furious that children with the condition today are being dosed with drugs that 'destroy so much potential'

Will.i.am is in the middle of a speech and the Voice judge will not be interrupted because he has an impassioned point to make. He is berating the widespread practice of medicating children who suffer from ADHD (attention deficit hyperactivity disorder). 'Listen,' he says. 'It's not the kids who are the problem, it's the lazy parents and lazy teachers who want kids to take Ritalin [a stimulant commonly prescribed to suppress the condition]. You don't need medication, you need patience with kids who have ADHD. We need to deal with this issue because it is getting out of hand. It's destroying so much potential and no one gives a damn.'

No one gave much of a damn about a small, 12-year-old bespectacled boy called William James Adams three decades ago. He was born in the poor Estrada Courts housing projects in Los Angeles, and few of the teachers at his school, where he was diagnosed with severe ADHD, would have expected the mouthy, body-popping prankster in the playground to become a multi-millionaire musician.

Will.i.am is a seven-times Grammy winner, philanthropist, World Economic Forum contributor and speaker at Bill and Melinda Gates's Goalkeepers debate on global issues

The founder member of The Black Eyed Peas is also one of the longest-serving judges on The Voice, a seven-times Grammy winner, philanthropist, World Economic Forum contributor and speaker at Bill and Melinda Gates's Goalkeepers debate on global issues. 'That was the only time in my life I've ever been nervous,' he admits. 'I felt like I'd swallowed a glass of sand, but I pushed through because I'd been asked to share my thoughts on education and technology.'

Will.i.am has no formal qualifications yet spends a significant amount of time at education conferences around the world, as well as questioning why more investment is going into artificial intelligence than human intelligence.

'Think about it,' he exclaims. 'In 20 years we will have mobile phones that are smarter than our kids. And that's a crazy situation.'

His teachers never particularly rated him at school because, educationally, he had a problem – ADHD – and his single mother, Debra, chose not to give him Ritalin. Yet he believes his success is not in spite of his ADHD but because of it, as it gave him the creativity that he's funnelled into music, the energy to work 24/7 and the freedom from having to go the traditional route into college and follow his own path.

'I was fine because I had a patient mother and some patient teachers, but it makes me furious that you get a kid who has this creative energy, who is powering off the walls and people can't be bothered to deal with that energy. They just want to medicate it away.

'You'll get a teacher who says to a parent, 'Your child is not like the rest of the kids. He talks all the time, he runs about, he's into everything but there is a pill you can give him to slow him down.' Why? Why not encourage that energy, direct it, have the patience to develop it and harness it?

'I am so happy that I was never made to take Ritalin. My mum couldn't have afforded it because we had no money, but she also wasn't afraid to say, 'No. Leave my kid be.' ADHD was never my problem. I thought of it as a gift because it gave me an ability to join dots. I think creatively but I find technology more fascinating than producing music because the possibilities are endless. I look at the past and see the connections with the future, and that excites me and drives me forward to do more things with my life.

'What's wrong with our society is that we want to pull everything back, stop people thinking out of the box and make everyone the same. I've never wanted to be the same as anyone else. I don't fear the future, I don't fear change, I don't fear the rise of artificial intelligence, because it's coming and it's going to change everything, like electricity did.'

We are sitting in a deserted cinema in the East End of London. Will.i.am arrived 20 minutes early, complete with security, management, assistant and stylist – the full superstar retinue. He is wearing a black beanie and an all-black outfit that might be described by a fashion magazine as 'luxe combat wear'. He eats a plate of mashed avocado and jokes around with his crew. He is very good at being a celebrity as he likes the interaction. 'I like to talk,' he laughs, then adds, 'As long as you listen.'

He says he never doubted he was going to be successful and looks surprised when I ask if he feels lucky that he never succumbed to one of the many drug-dealing gangs that hung about outside his childhood home.

'Why do people assume that could be your only option? That was never even a consideration. There are always choices. I come from those streets but I have two cousins who became professional sportsmen. I was going to be a pro sportsman. I was great at football and track, I was fast as hell. But then I got concussion after a football accident and I sat on the bed and told my older brother Carl, 'No more sports. I'm not risking my head like this. From now on, I'm all about music.'

I ask where he got this sense of self-assurance that he would succeed, and he replies with a seemingly random answer: 'Houses.'

I look puzzled and he laughs. His habit of just giving his 'end thought' is part of the reason he's always so watchable on The Voice. As entertainment, it works, but his actual thought processes require more than just a soundbite to make sense. The real will.i.am is far more serious than the face-pulling eccentric he presents on television.

Will.i.am and mother Debra Cain attend NASA (left): Will.i.am as as a fresh-faced schoolboy (right)

Back to the houses. 'My mum sent me to a school outside our area in Brentwood. The kids there had big houses. I'd go round to a friend's, look at the house and think, 'How do they get to live in a place like this?'

'I'd always wait for their dad [he has never met his own father, who walked out on the family when he was a baby] to come back from work and ask that question. I heard so many stories about how this family had rocked up in America with just $50 or with nothing and they had gone out and worked and worked. It might have been in a restaurant or selling pairs of jeans. But every story had the same basic message: it was all about how hard you worked and how you used any opportunity you had and then with what you earned you provided for your family. So coming from my little apartment and sitting in friends' houses taught me that secret – whatever you do you have to work really, really hard to get there.'

He's got a feeling... Car or space rocket? Never a space rocket. Maybe by cellular particle technology when that happens. Savile Row suit or Adidas tracksuit? Adidas tracksuit – I can work, I can exercise all in one outfit. Tom Jones or Olly Murs? Always Tom Jones. I could sit for hours talking to him. He's a very wise, very knowledgeable man. iPhone or Fitbit? iPhone. You can do everything on an iPhone. Full English breakfast or kale and spinach shake? Kale and spinach shake – as long as there's no dairy in it. Ed Sheeran or Michael Jackson? Michael. Always. Advertisement

He was 13 when he and two school mates, Allan Pineda (aka apl.de.ap) and Dante Santiago, started performing around Los Angeles, winning attention from the rapper Eazy-E, who, in 1992, signed them to his Ruthless Records label – when they officially became The Black Eyed Peas. The group went on to sell 76 million records (with hits like I Gotta Feeling, Where Is The Love? and My Humps). But the way will.i.am worked was unconventional – the band was a co-operative, drafting in other singers, including Fergie (Duhamel), or collaborating with Justin Timberlake and Macy Gray. By 2009, he had worked with everyone from Lady Gaga to Britney Spears, U2, Prince and Michael Jackson.

Music was not, however, will.i.am's end game. 'Never was,' he says. His celebrity status gave him the money and the platform to mix with the greatest technology brains of our generation. He went to weekend think-tanks on human genome sequencing and immersed himself in the hi-tech world of Silicon Valley as he looked to develop new businesses. 'I always look ahead and look behind,' he says. 'When I was 20 I was thinking of being 30. Last year I was told I had high cholesterol and blood pressure. I started thinking what my 60s would look like, so I've become vegan and I'm much better for it, even though I miss yellowtail with jalapeño.'

In 2005, when he was 30, will.i.am moved every member of his family out of the projects, buying them houses close to the LA property he bought his mother when he was 23. Four years later, he set up a scholarship programme in Boyle Heights, the run-down neighbourhood where he grew up. So far he has raised millions for scholarships and seen scores of kids through college. Will.i.am has also diversified into recycling and fashion, invested in the Pinterest social network and acted in movies from X-Men to Date Night.

In 2011 he began as a judge on The Voice and moved to ITV when it was poached from the BBC for £335 million a year ago. Last week it was revealed that he's teaming up with Voice co-judge Tom Jones to record a single.

Music was not will.i.am's end game. 'Never was,' he says. His celebrity status gave him the money and the platform to mix with the greatest technology brains of our generation

We are here today to talk about The Voice, where he sits on the famous red swivel chairs alongside Jones, Olly Murs and Jennifer Hudson. While he has risen from nowhere to succeed, the prime-time talent show has yet to find a winner who's been able to rocket to pop stardom. And in his tech business he has yet to make a product that changes the world, with many of his apps and his attempt at designing a smartwatch being savaged by critics. He rolls his eyes when I make the point.

'Everything I do gets criticised,' he says. 'But the thing is, I am doing it and I understand that you have to keep doing, keep going to get it right. On The X Factor they have had big stars [from One Direction to Leona Lewis], but that is because Simon Cowell is an executive on the show and he runs the record company that takes them on, so it's his business to make sure they have the backing and everything behind them to make them stars.

'The Voice is more realistic. I love that show. I never get bored because I believe that one day the next Drake is coming and that is going to happen. But it's not that simple. We provide a platform. We give them the chance and then it is up to them. It's tough out there, and you have to work.

Will.i.am is a judge on The Voice alongside Tom Jones, Olly Murs and Jennifer Hudson

The Black Eyed Peas. The group sold 76 million records (with hits like I Gotta Feeling, Where Is The Love? and My Humps)

'In The Black Eyed Peas we worked 24/7 to make things happen. Failure wasn't an option. 'I felt a duty to become successful for my family and for my friend Apl, who came to America from the Philippines. I was the first person he met at school when he was 14 years old. He spoke no English but we connected, and when he agreed to go with the band instead of going to college when he was 18, his dad said he had to leave the house. We both cried because if we didn't make a go of it, then his whole mission to come to America had failed and it was on me to make it happen.'

He returns to his deeply held mantra: 'It's all about work. You need to be prepared to stand up, get knocked down and stand up again. Society has created a lot of snowflakes and social media has created a generation of kids who think they can be Beyoncé or Michael Jackson on social media. You don't get to be that person unless you give it everything.'

Will.i.am was the last person to work with Michael Jackson before he died in 2009, and has consistently refused to allow the catalogue of songs he made with the singer to be released – despite the fact he would make millions. He has firm views on this. 'I would never do that. I grew up obsessed with Michael Jackson. When he called me to ask him to work with him I didn't believe it was him. But those songs weren't perfected in the way someone like him wanted them to be perfected. You don't do that. You have integrity. You respect the legacy.'

Will.i.am was the last person to work with Michael Jackson before he died in 2009, and has consistently refused to allow the catalogue of songs he made with the singer to be released

I attempt to move the subject on to his own legacy in terms of getting married and having children. At 42, he is single and childless and has said in the past he finds romantic love 'painful' and is constantly put in the 'friend zone' by women. He lives in a large house ('not a mansion') and his neighbour is Natalie Portman, who he is planning on visiting when he returns from London. 'I saw her film Annihilation, which just blew my mind. I need to knock on her door and tell her that.

'I don't want to talk about marriage and kids. But it is completely egotistical to think that a legacy is all about you having children. For me, a legacy is the things you do. I have a whole generation of kids from my streets going to college and being educated, I'm part of a movement of people working in technology and artificial intelligence trying to make a better future. Today we have racism, sexism, a celebrity president, Donald Trump, and that's scary. Tomorrow we can make it a better world.'

'The Voice UK' continues on ITV, Saturdays at 8.30pm. The new Black Eyed Peas single, 'Street Livin', is available now across all digital platforms