Randolph Nesse is a pioneer in what he argues is a new way of thinking about psychiatric disorders and the science of mind. He sees his work as a branch of Darwinism. This intriguing book turns some age-old questions about the human condition upside down: “Why,” Nesse wonders at the outset, “do mental disorders exist at all? Why are there so many? Why are they so common?” Surely, he suggests, “natural selection could have eliminated anxiety, depression, addiction, anorexia and the genes that cause autism, schizophrenia and manic depressive illness. But it didn’t. Why not?”

Nesse, formerly both a professor of psychology and psychiatry and now the director of the Center for Evolution and Medicine at Arizona State University was never, of course, going to offer definitive answers to these questions. Rather, in an engaging, storytelling voice that rests on 30 years of clinical practice, he offers a series of insights, both scientific and anecdotal, that begins to show why the vulnerabilities in our psyche are fundamental to the survival of our genes. Nesse is properly dismissive of suggesting a direct evolutionary purpose in depression or anxiety – “disorders don’t have function” – rather, he argues, they represent an excess of what it means to be human. “Our suffering often benefits our genes,” he argues.

Part of Nesse’s inquiry stemmed from the inadequacy of our current piecemeal strategies for treating mental disorders of all kinds; that spectrum of alternatives that runs from prayer and mindfulness through cognitive therapies and psychoanalysis to pharmacology and hospitalisation. In each case, the suffering is seen as a quasi-medical condition, rooted in psychology or physiology. An evolutionary view of these conditions attempts to broaden that perspective. It derives from the fact that “our brains were shaped to benefit our genes, not us… Natural selection does not give a fig about our happiness.”

Part of Nesse’s practice with patients involves explaining to them that, in many cases, their disorders are not a disease or some kind of failing, as they have been told by other practitioners, but rather a natural and inherently useful response that has “gone overboard”. Evolution makes women on average twice as prone to excessive anxiety as men for good reason. Nesse reports that patients who experience panic attacks are invariably “normalised and empowered” by such a perspective.

Similarly, those who experience prolonged low mood may be, if not comforted or cured, then perhaps illuminated by the notion that their state of mind has a role to play in Darwinian terms. Nesse presents the evidence to show that the mechanisms of despair have evolved to force us to realign our goals and desires: we would never be forced to make positive choices to influence our circumstances were it not for the anger at loss in our lives or the pain of not reaching our goals. Samuel Beckett’s “Ever tried. Ever failed. No matter. Try again. Fail better” might be the guiding philosophy of our genetic makeup.

A crucial element of Nesse’s book is his clear-eyed insistence that “evolutionary psychiatry” itself cannot cure or prevent disorders, but it can approach them with new questions. He points to the interesting research into eating disorders that presents them as a possible result of a “predictive adaptive response” in the womb – the idea that limited nutrition in utero could change the way that the metabolism stores and processes calories. This change, in turn, could be passed on genetically so that the obesity risk of a child, or a propensity to anorexia, “may be influenced by a mother’s or a grandmother’s diet”. Such adaptive responses are “intrinsically vulnerable to going out of whack”. The result of this, Nesse suggests, is not that we should expect to isolate the defective genes responsible for eating disorders, but that the knowledge helps to explain why extreme dieting can trigger both anorexia and excessive weight gain.

His book, a mixture of such research and well-caveated speculation, addresses the thornier questions of psychiatry with a pragmatic curiosity. He makes a strong case that the current obsessions with population genetics and neuroscience are unlikely to unlock answers to the most complex problems. He hopes that an “evolutionary perspective on dire mental diseases shifts attention away from the easy assumption that because they are influenced by genes, they are caused by defective genes”. Rather, he hopes that his approach will open up inquiry into the “traits, fitness landscapes and control systems that may result in vulnerability”. He offers no promise, as yet, that this approach will quickly generate a raft of new cures. Instead, he argues, it will help us make sense of all the manifestations of the most insistent of modern epidemics. Truisms that suggest grief is the price we pay for love or that suffering is the cost of desire are not trivial in this regard. That there are “good reasons for bad feelings” appears to be written in our DNA.

• Good Reasons for Bad Feelings is published by Allen Lane (£20). To order a copy go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99