Some of the doctors began to ask how this fitted with the grief exception. If the symptoms of depression were a logical and understandable response to one set of life circumstances – losing a loved one – might they not be an understandable response to others? What if you lost your job? If you were stuck in a job you hated? If you were alone and friendless? The grief exception seemed to have blasted a hole in the claim that the causes of depression were sealed away in your skull. It suggested that there were causes out in the world, and that they needed to be investigated and solved out here, in the world. This was a debate mainstream psychiatry (with some exceptions) did not want to have. So they responded in a simple way – by whittling away the grief exception. With each new edition of the manual, they reduced the period of grief allowed before being labelled mentally ill – down to a few months and then, finally, to nothing. Now, if your baby dies at 10am, your doctor can diagnose you with a mental illness at 10.01am and start drugging you straight away. Some 32 per cent of grieving parents in the US are drugged within the first 48 hours. Dr Joanne Cacciatore of Arizona State University became a leading expert on the grief exception after her own baby, Cheyenne, died during childbirth. She tells me that this debate reveals a key problem with how we talk about depression, anxiety and other forms of suffering: we don't, she says, "consider context". If we start to take people's actual lives into account when we treat depression and anxiety, she explains, it will require "an entire system overhaul". "When you have a person with extreme human distress, [we need to] stop treating the symptoms," she says. "The symptoms are a messenger of a deeper problem. Let's get to the deeper problem." Australia has the second highest rate of antidepressant use in the world, with nearly one in 10 Australians taking them. Illustration by Getty Images Credit:Getty Images

There is nowhere I went to, in the research for my new book, Lost Connections: Uncovering the Real Causes of Depression – and the Unexpected Solutions, that needs to think about this more urgently than Australia. On the entire planet, only one country, Iceland, has a higher rate of use of antidepressants. Since 2000, this rate has more than doubled, and nearly one in 10 Australians are taking them. They are even being prescribed to more than 1000 children aged between two and six. It's a sign of a deep crisis. When I was a teenager, growing up in London, I went to my doctor and explained that I felt pain was leaking out of me uncontrollably, like a bad smell. He told me a story – the story that has subsequently conquered Australia. He said there is a chemical called serotonin that makes people feel good, and that some people are naturally lacking it. You are clearly one of them. Take these drugs, and you will be normal again. I believed and preached this story for 13 years – but there was something painful to admit. Apart from short pockets of relief, I remained depressed, no matter how many of these pills I took. I thought I was weird. But when I spent three years travelling all over the world researching what is really causing this crisis, I learnt something startling. I was totally normal. Between 65 and 80 per cent of people taking chemical antidepressants become depressed again, according to the clinical psychologist Dr Steve Ilardi and research published in the New England Journal of Medicine. There is a real effect – but, alas, for many users, it's not enough to lift them out of depression. I don't want to take anything off the menu for depressed people, but it's clear we need to add far more to it. We are the first humans to try to live alone and to imagine we can provide what we need for ourselves, as isolated individuals.

Dr Christopher Davey at the University of Melbourne, who has done some of the most interesting Australian research on this question, explains that the story I and millions of others were told by our doctors about why we were depressed is false. "The idea you could reduce it to one neurotransmitter [like serotonin] is obviously, obviously absurd. I don't think anyone seriously believes that … That's just absolute nonsense," he says. "It has much more to do with social connectedness, and social supports." There is scientific evidence for nine different causes of depression and anxiety. One thing connects them. We all know human beings have natural physical needs: for food, water, shelter. It turns out human beings have natural psychological needs, too – but Australian society, and the wider Western world, is not meeting those needs for many of us, and that is the primary reason why depression and anxiety are soaring. For example, there has been an explosion in loneliness. Australian social researcher Hugh Mackay has his own theory. "The biggest contributor is social fragmentation," he says. "Humans are social animals. We need communities. "The story of Australia over the past 50 years – accelerating over the past 20 years – has been the story of those traditional groupings coming apart. There's been much more social fragmentation." Why is this causing so much distress?

Human beings evolved to live in closely knit tribes that were constantly co-operating. We only survived as a species because we could work together so tightly, and take down animals bigger and stronger than us. Just as a bee's instincts are to connect with a hive, a human's instincts are to connect with a tribe. But we are the first humans to try to live alone and to imagine we can provide what we need for ourselves, as isolated individuals. In the circumstances where humans evolved, if you were apart from the tribe, you would feel depressed and anxious for a very good reason – you were in terrible danger. "When you have an epidemic of anxiety and depression, that is a societal warning bell," Mackay says. "If we don't attend to that warning bell, we're in for a very difficult future." To begin to respond, we need to shift the way we think about this problem. In the early 2000s, South African psychiatrist Derek Summerfeld went to Cambodia, at a time when antidepressants were being introduced there. He began to explain the concept to the doctors he met. They listened patiently and told him they didn't need these new antidepressants, because they already had some that worked. He assumed they were talking about a herbal remedy. He asked them to explain, and they told him about a rice farmer they knew whose left leg was blown off by a landmine. He was fitted with a new limb, but he felt constantly anxious about the future, and was filled with despair. The doctors sat with him, and talked through his troubles. They realised that even with his new artificial limb, his old job – working in the rice paddies – was leaving him constantly stressed and in physical pain, and that that was making him want to just stop living. So they had an idea. They believed that if he became a dairy farmer, he could live differently. They bought him a cow. In the months and years that followed, his life changed. His depression, which had been profound, went away. "You see, doctor," they told him, the cow was an "antidepressant". To them, finding an antidepressant didn't mean merely finding a way to change your brain chemistry. It meant finding a way to solve the problem that was causing the depression in the first place.

I interviewed huge numbers of scientists who were trying to find ways to do that, and learnt about seven antidepressants that really work. For example, in a surgery in east London, a doctor named Sam Everington was becoming uncomfortable. Patients were coming to him depressed because they were lonely – and he was drugging them. So he began an experiment. He "prescribed" for them to take part in a group activity. One patient had been shut away in her home for seven years. He prescribed for her to take part in a gardening group, where she and other depressed people were given a patch of scrubland, and asked to make it into something beautiful. Over the next year, slowly, she began to reconnect with the land, and with the other depressed people in the group. Today, she is free from depression, and running a gardening centre. That grief and depression have the same symptoms isn't a coincidence. Depression is a form of grief – for your life not going as it should; for your psychological needs not being met. With grief for somebody who has died, we offer love and support to the people who remain. With grief for our lives going wrong, there's a different solution – one that is lying there, waiting for us. It is a program of deep reconnection with the things that really matter in life. Lost Connections: Uncovering The Real Causes of Depression and Anxiety – and the Real Solutions by Johann Hari (Bloomsbury, $28), is out now.