Want to feel happier? Then smile, eat seaweed, get a new hairstyle, send fewer emails, go dancing, spend less money - and don't just pop pills. Or so says one of the world's most eminent scientists.
In a controversial new book, Professor Jane Plant proposes a raft of unorthodox treatments for the millions who suffer from anxiety, stress and depression.
Instead of just popping 'happy pills' such as Prozac to beat the blues, Plant and her co-author, Janet Stephenson, advise sufferers to take steps such as avoiding dairy products, sending fewer text messages, eating porridge at night and playing card games. They say all their tips are based on hard scientific evidence gathered from studies around the world.
"Smiling is a way of tricking your brain into thinking that everything's OK, even if it's not," said Plant. "People who are mildly depressed should do their best to show the world a happy face as that will improve people's reaction to you and lift your mood."
In Beating Stress, Anxiety and Depression, Plant and Stephenson urge a radical overhaul of the way health services treat the soaring number of people with some form of mood disorder.
They advise sufferers to increase their intake of mood-boosting chemicals by eating kippers or poached haddock for breakfast because they contain omega-3 fatty acids, and to be less materialistic, as those who achieve success may do so at the expense of personal relationships, which are a better guarantee of happiness.
The authors are serious figures. Plant, a professor of environmental geochemistry at Imperial College in London, is the UK government's chief advisor on toxic chemicals and a trustee of Prince Charles's Foundation for Integrated Medicine, while Stephenson is a psychologist working within the National Health Service.
"We do not agree with the usual advice to keep taking your medication and eventually all will be well, because doctor knows best," they write.
"We challenge many of the conventions in the treatment of mental illness."
The authors say their aim is to empower people suffering with a mental disorder.
They say that anyone with low self-esteem should ignore celebrity culture as much as possible because it may make them feel even worse when they don't match up to pop stars or TV presenters.
They also recommend improving your appearance through a new hairstyle, clothes or make-up because this can improve self-confidence. And people should definitely smile, even if they are feeling down.
One in six people can expect to experience depression, however briefly, at some point in their lives and millions are affected by an anxiety disorder. A large-scale study recently suggested that Prozac and similar drugs may have little value.