Johann Hari is a writer and author of several books, and a former columnist for the Independent. His latest book, Lost Connections, explores the causes and cures of depression and anxiety. It argues that the notion of inherent depression has been overstated, and that environmental factors are too often neglected. In 2011, he was the subject of accusations of plagiarism that led to the end of his career as a newspaper columnist.

You started work on the book, you say, because you were puzzled by several mysteries. But did you have an idea of what conclusions you would come to?
I think most of the things that are in the book I had inklings about. For many years I had wanted to find out what causes depression and anxiety and how to really solve them. However, I was afraid that if I dismantled the story that I had about depression and anxiety – even though that story hadn’t worked well for me – I would have no story at all, and it would feel really chaotic, and I would feel really vulnerable. For the 13 years during which I was taking antidepressants, despite some doubts, I did believe in the theory that saw chemicals as the main approach.

As well as taking antidepressants, you’ve seen a therapist for 14 years. How effective has that been?
There are three kinds of causes of depression and they interact. There’s the biological causes, which are real, and can make you more vulnerable to depression, but don’t cause it on their own. There’s environmental causes, which are about how we live together socially. And then there are psychological causes, which are about how we think about the world. Clearly, therapy speaks most to the psychological causes, which are very real. Therapy helped me to think about that aspect of it.

Do you think that therapy has worked for you?
I experienced some quite extreme acts of violence when I was a child, from an adult in my life, when my mother was very ill and my father was in another country. I felt a significant fall in depression once I was eventually able to talk about those experiences with my therapist. Given that we have the evidence that therapy does indeed help with the specific area of the psychological causes of depression, I think it’s fair to assume that, when therapy is done well, it can also help with other forms of depression.

Why do you think it is that doctors hand out so many antidepressants when the wealth of evidence as you present in your book suggests they are largely ineffective?
I wouldn’t want to overstate their ineffectiveness. Between 65 and 80% of people taking antidepressants become depressed again within a year. However, that’s not 100%. Of course some people would have recovered anyway through natural processes. I’m not critical of doctors for this. Part of the problem is that we’ve put the onus for solving these problems on to people who are not in a position to solve them alone. Telling people, as I was told by my doctor, that depression is caused by a problem in your brain is, firstly, untrue and it is also really problematic because it cuts people off from finding the real causes of their depression and anxiety. We’ve been telling ourselves this chemical story for 35 years and every year depression and anxiety gets worse.

Why are depression and anxiety issues on the increase?
The umbrella answer is that human beings have innate psychological needs just as we have physical needs. We need to feel we belong, that we have meaning and purpose, that people value us and that we have autonomy. We also live in a culture that’s not meeting those psychological needs for most people. It does not manifest as full-blown depression and anxiety in most people; for some people it’s just a feeling of unhappiness and a life less fulfilling than it could have been. We’ve built a society that has many great aspects, but it is not a good match for our human nature.

In the book you mention a crisis in your life that was “unequivocally terrible”. Was that when you lost your job at the Independent in 2011 and returned your Orwell prize, after being accused of plagiarism?
Yes, it was that, in combination with someone I love very much having a bad addiction crisis. Just to outline events, because some people won’t know, I did two things that were completely wrong. One is that when I interviewed people I often presented things that had been said to other journalists or had been written in books as if they had been said to me, which was not truthful. The second is that I edited Wikipedia entries regarding other people under a pseudonym and, sometimes, in very nasty ways.

Most people who go through your experience tend to flee from public view. You’ve come back and had success. Has that been a difficult process?
When you fuck up and do several things completely wrong, as I did, it should really hurt. And you should pay a really big price. It did hurt and I did pay a really big price, as is entirely right. The reason I’m reluctant now to go into how that felt for me is because that’s saying to people “see it from my point of view”. However, I don’t think that they should see it from my point of view. I think they should see it from the point of view of those people who were harmed by me: my readers, the people I was nasty about and the people at the Independent that I let down.

Have you apologised to the people who were affected by your Wikipedia tampering?
Yes, I wrote to two of the individuals involved, and I’d rather keep private what was said.

Has what you’ve learned by writing this book helped to alleviate your depression? Are you, for want of a better phrase, a happier person?
Massively, but I want to just caveat that. What this book is not is a simplistic guide saying: “Hey, I did these things, and now you can do them too.” I think that would be quite cruel because I was in this incredibly privileged position. I had money from my previous book, which meant that I could change my life in quite radical ways in order to strip out some of the causes of my depression. Lots of people are not in a position to do that.

A big part of the argument of the book is to say that we need to change our culture so that more of us are free to do the things that I was very fortunate to be able to do. In my own life I’ve been able to devote much less time to seeking status and external achievement and much more to engaging with what I think really matters, the people I love and the causes that I think are important. Before, when I started to feel bad, I would have done something for myself. Now, I can see it’s better to cheer someone else up. That’s had a radical effect on my mental health.

If you are affected by depression or suicidal thoughts, there are places you can turn to. In the UK, Samaritans can be contacted on 116 123. In the US, the National Suicide Prevention Lifeline is 1-800-273-8255. In Australia, the crisis support service Lifeline is on 13 11 14. Other international suicide helplines can be found at www.befrienders.org.

• Note by readers’ editor, Paul Chadwick, added 7 February 2018: After publication, I considered a complaint relating to Guardian and Observer coverage of the book: an extract; this Q&A with the author; review; blogpost on 8 January; and blogpost on 24 January. I concluded that the book’s author, Johann Hari, and his critic in the blogposts, Dean Burnett, were entitled to their differing views, and that the Guardian and Observer editorial standards had been met. Due to the sensitivity of the issue involved - namely, the causes and treatment of mental illness - I also concluded that it was appropriate to emphasise for readers that the author and his critic have both expressed the view that people taking anti-depressants should not stop taking their medication abruptly or without seeking professional advice.