Anxiety and its next of kin, fear, are arguably the oldest, most basic human emotions, bequeathed to us by a vast history of prehominid ancestors. We owe our survival as Homo sapiens to these emotions, which were literally built into our nervous systems as an evolutionary hedge against extinction. Yet today, while still protecting us from genuine danger, they’ve morphed into a multitude of extraneous and dysfunctional afflictions—panic disorder, obsessive-compulsive disorder, phobias, and all-purpose generalized anxiety disorder (summoning up anxieties on any and all occasions)—the only effect of which seems to be to torment us pointlessly.

When I began my practice, psychotherapists still knew precious little about anxiety, even though it was probably the commonest form of suffering among the clients we saw. By and large, it was considered a symptom of some deeper psychodynamic process, and analysts helped clients find the deep-seated meaning behind their fears. The working Freudian hypothesis of agoraphobia in women, for instance, was that they withdrew to their homes out of an unconscious fear that they’d become prostitutes.

It wasn’t until the 1960s, when behavioral psychologist Joseph Wolpe’s experimental research perfected relaxation techniques and systematic desensitization, that anxiety began to be treated as a separate problem. To treat a fear of dogs, for instance, Wolpe taught the patient how to become deeply relaxed. He then introduced…