A Gene for Anxiety !!!

If the degree to which we are prone to negative thinking, anxiety, and depression are genetically determined, what implications does this have for Cognitive Therapy?

A study by Lesch et al. (1996) found that the amount of _neuroticism_, a trait related to anxiety and depression in humans, is influenced by two alleles of a gene which encodes a transporter for the neurotransmitter serotonin. One allele results in more of this protien - and more neuroticism - and the other, less protein and less neuroticism. It has been estimated that neuroticim is 40-60% heritable and that this particular allele accounts for 3-4% of the variability in neuroticism. Lesch et al (1996) predict that a total of 10-15 genes may be involved in all.

_Neuroticism_ is not a concept that usually receives a great deal of attention in cognitive-behavioral circles (since we tend to focus on specific disorders). However, this finding is relevant since level of _neuroticism_ is related to risk of depression and of anxiety disorders. In addition to being related to _neuroticism_, the gene in question also was significantly related to measures of more specific traits including Harm Avoidance, Worry and Pessimism, and Fear of Uncertainty. These are clearly relevant to clinical practice.

One could argue that, if some individuals are anxiety-prone due to genetically determined abnormalities in their serotonin metabolism, we should use pharmocological rather that psychotherapeutic interventions. After all, doesn't this study demonstrate that we are dealing with a biological disorder?

It seems to me that there are a few flaws in this arguement. First, if _neuroticism_ is 40-60% heritable, what proportion of _neuroticism_ is not accounted for by heritability? (40-60%) Second, the finding that biological factors play a role in a disorder does not mean that environment/learning/psychology is irrelevant. (Many disorders are the product of complex interactions between biology and environment.) Third, even if a disorder is completely biological in origin, this does not necessarily mean that the treatment needs to be biological. Finally, the efficacy of cognitive-behavioral treatment for anxiety disorders, and depression, etc. has been well established. Cognitive-behavioral (and other) treatments work and the finding that genes play a role in the disorder does not change that.

Lesch et al (1966) suggest that once the genetics relevant to anxiety (and other) disorders are understood, individualized pharmacological interventions may be possible. However, this type of intervention lies far in the future and my bet is that, even then, psychotherapeutic intervention will be needed in combination with meds.

Reference:

• Lesch, K., Bengel, D., Heils, A., Sabol, S.Z., Greenberg, B.D., Petri, S., Benjamin, J., Muller, C.R., Hamer, D.H., & Murphy, D.L. (1996). Association of anxiety-related traits with polymorphism in the serotonin transporter gene regulatory region. Science, 274, 1527-1531.

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