We live in the Age of Anxiety.

In any given year, about 18 percent of Americans will suffer from an anxiety disorder. This is twice the rate as that for depression—though the latter seems to receive more attention. Over the course of a lifetime, the number who will suffer from anxiety rises to close to 30 percent. Is there anything we can do?

As individuals we have choices as to how to deal with anxiety. We also have opportunities we did not have before. Modern psychology has learned a great deal about anxiety in the last few decades. We know much more than we once did about where it comes from, how it operates on the mind, the nature of the behavioral patterns it generates. All this can help us understand the role that anxiety plays in our lives. And understanding that role is the key to overcoming anxiety—not to eliminating it completely, for that’s not a realistic goal. But we can learn to neutralize it, control it, and keep it from being a debilitating force that restricts our health and freedom. Understanding anxiety, in short, is the way to escape its tyranny.

The first thing to understand about anxiety is that it’s part of our biological heritage. Long before any recorded human history, our ancestors lived in a world filled with life-threatening dangers: predators, starvation, toxic plants, hostile neighbors, heights, disease, drowning. It was in the face of these dangers that the human psyche evolved. The qualities necessary to avoid danger were the qualities that evolution bred into us as human beings. A good many of those qualities amounted simply to different forms of caution. Fear was protective; one had to be wary of many things to survive. This wariness persists in our present psychological makeup in the form of some of our deepest aversions and phobias. These fears were adaptive—they are really survival instincts left over from a primitive era.

The next thing to understand is that, since we no longer live in that primitive world, the fears we carry from it are no longer adaptive. Thanks largely to the effects of language and civilization, the challenges we encounter in our lives are quite different from the ones our ancestors faced on the savanna or in the jungle. Yet our brains continue to operate as though nothing has changed. We’re driven by the instinct to run from a hungry jaguar when all we may be confronting is a barking dog. We’re afraid to touch a plate someone has used because our ancestors had a healthy aversion to contaminated food. We feel pathologically shy because, in another era, a stranger could easily kill us; even a member of our own tribe might do harm to us if offended. When it comes to our deepest instincts, we act as though we are still in the Stone Age, facing Stone Age conditions.

We are, in short, operating on an outmoded set of “rules.” Evolution has programmed these rules into us as a way of protecting us from risk. They’re like a kind of software installed in our heads—software that’s millions of years old. Every instinct we have tells us that obeying the rules will keep us safe, when, in fact, just the opposite may be true. Our method of breaking free from the tyranny of anxiety is to challenge these rules—in effect to rewrite them. This involves examining the irrational beliefs that the rules are based on. For these beliefs, when unquestioned, exert a hidden but enormously powerful influence over our thoughts and behavior.

Once we challenge these beliefs, we can begin revising the rules governing anxiety, even though the latter are embedded deeply in our mind. Why are we able to do this? Because nature, in addition to providing us with certain instincts, has also given us the ability—located for the most part in a different part of our brain, the part we call rational—to modify those instincts on the basis of our experience. This is the key to treating anxiety. It is not the same as “being rational” about our fears. This does not work: knowing or being told that a fear is irrational does not make it go away. But if we can actually experience a seemingly dangerous situation over and over again, but without harmful consequences, our brains learn to be more rational and less fearful. It happens all the time in life. All it takes is to set up a program in which we can have a certain fearful experience regularly but in a context that teaches us it is safe. Thus over time we learn to lessen our fear.