Monday, May 27, 2013

Cognitive-bias modification (CBM)

A great article from The Economist, which has great science coverage. I don't know much about this CBM business, but I will look into it.

THE treatment, in the early 1880s, of an Austrian hysteric called Anna O is generally regarded as the beginning of talking-it-through as a form of therapy. But psychoanalysis, as this version of talk therapy became known, is an expensive procedure. Anna's doctor, Josef Breuer, is estimated to have spent over 1,000 hours with her.

Since then, things have improved. A typical course of a modern talk therapy, such as cognitive behavioural therapy, consists of 12-16 hour-long sessions and is a reasonably efficient way of treating conditions like depression and anxiety (hysteria is no longer a recognised diagnosis). Medication, too, can bring rapid change. Nevertheless, treating disorders of the psyche is still a hit-and-miss affair, and not everyone wishes to bare his soul or take mind-altering drugs to deal with his problems. A new kind of treatment may, though, mean he does not have to. Cognitive-bias modification (CBM) appears to be effective after only a few 15-minute sessions, and involves neither drugs nor the discussion of feelings. It does not even need a therapist. All it requires is sitting in front of a computer and using a program that subtly alters harmful thought patterns.

This simple approach has already been shown to work for anxiety and addictions, and is now being tested for alcohol abuse, post-traumatic-stress disorder and several other disturbances of the mind. It is causing great excitement among researchers. As Yair Bar-Haim, a psychologist at Tel Aviv University who has been experimenting with it on patients as diverse as children and soldiers, puts it, “It's not often that a new evidence-based treatment for a major psychopathology comes around.”

Don't talk about it, just do it

CBM is based on the idea that many psychological problems are caused by automatic, unconscious biases in thinking. People suffering from anxiety, for instance, may have what is known as an attentional bias towards threats: they are drawn irresistibly to things they perceive to be dangerous. Similar biases may affect memory and the interpretation of events. For example, if an acquaintance walks past without saying hello, it might mean either that he has ignored you or that he has not seen you. The anxious, according to the theory behind CBM, have a bias towards assuming the former and reacting accordingly.

The goal of CBM is to alter such biases, and doing so has proved surprisingly easy. A common way of debiasing attention is to show someone two words or pictures—one neutral and the other threatening—on a computer screen. In the case of social anxiety these might be a neutral face and a disgusted face. Presented with this choice, an anxious person instinctively focuses on the disgusted visage. The program, however, prods him to complete tasks involving the neutral picture, such as identifying letters that appear in its place on the screen. Repeating the procedure around a thousand times, over a total of two hours, changes the user's tendency to focus on the anxious face. That change is then carried into the wider world.

Emily Holmes of Oxford University, who studies the use of CBM for depression, describes the process as like administering a cognitive vaccine. When challenged by reality in the form of, say, the unobservant friend, the recipient of the vaccine finds he is inoculated against inappropriate anxiety.
In a recent study of social anxiety by Norman Schmidt of Florida State University and his colleagues, which involved 36 volunteers who had been diagnosed with anxiety, half underwent eight short sessions of CBM and the rest were put in a control group and had no treatment. At the end of the study, a majority of the CBM volunteers no longer seemed anxious, whereas in the control group only 11% had shed their anxiety. Although it was only a small trial, these results compare favourably with those of existing treatments. An examination of standard talk therapy carried out in 2004, for instance, found that half of patients had a clinically significant reduction in symptoms. Trials of medications have similar success rates.

The latest research, which is on a larger scale and is due to be published this month in Psychological Science, tackles alcohol addiction. Past work has shown that many addicts have an approach bias for alcohol—in other words, they experience a physical pull towards it. (Arachnophobia, a form of this bias that is familiar to many people, works in the opposite way: if they encounter a spider, they recoil.)

This study, conducted by Reinout Wiers of the University of Amsterdam and his colleagues, attempted to correct the approach bias to alcohol with CBM. The 214 participants received either a standard addiction treatment—a form of talk therapy—or the standard treatment plus four 15-minute sessions of CBM. In the first group, 41% of participants were abstinent a year later; in the second, 54%. That is not a cure for alcoholism, but it is a significant improvement on talk therapy alone.
Many other researchers are now exploring CBM. A team at Harvard, led by Richard McNally, is seeking volunteers for a month-long programme that will use smart-phones to assess the technique's effect on anxiety. And Dr Bar-Haim and his team are examining possible connections between cognitive biases and post-traumatic-stress disorder in the American and Israeli armies.

Not all disorders are amenable to CBM. One study, by Hannah Reese (also at Harvard) and her colleagues, showed that it is ineffective in countering arachnophobia (perhaps not surprising, since this may be an evolved response, rather than an acquired one). Moreover, Dr Wiers found that the approach bias towards alcohol is present in only about half of the drinkers he studies. He hypothesises that for the others, drinking is less about automatic impulses and more about making a conscious decision. In such cases CBM is unlikely to work.

Colin MacLeod of the University of Western Australia, one of the pioneers of the technique, thinks CBM is not quite ready for general use. He would like to see it go through some large, long-term, randomised clinical trials of the sort that would be needed if it were a drug, rather than a behavioural therapy. Nevertheless, CBM does look extremely promising, if only because it offers a way out for those whose answer to the question, “Do you want to talk about it?” is a resounding “No”.

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