

Testing Causality in Association Between Exercise and Symptoms of Depression - tokenadult
http://archpsyc.ama-assn.org/cgi/content/abstract/65/8/897

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tokenadult
A full text link is here:

[http://archpsyc.ama-
assn.org/cgi/content/full/65/8/897?ijkey...](http://archpsyc.ama-
assn.org/cgi/content/full/65/8/897?ijkey=ac20e9219798e35ace18edc4269c4c40efc8ce06)

I was told about this article overnight by a behavioral genetics researcher
who heard about this paper from his colleague. The twin study methodology used
here is a genetically sensitive design, which is still too rare in medical
studies. Both local researchers are surprised by the result reported in the
abstract (perhaps because both exercise regularly, as do most members of their
department of psychology). The abstract says,

"Context In the population at large, regular exercise is associated with
reduced anxious and depressive symptoms. Results of experimental studies in
clinical populations suggest a causal effect of exercise on anxiety and
depression, but it is unclear whether such a causal effect also drives the
population association. We cannot exclude the major contribution of a third
underlying factor influencing exercise behavior and symptoms of anxiety and
depression.

. . . .

"Design Population-based longitudinal study (1991-2002) in a genetically
informative sample of twin families.

. . . .

"Conclusion Regular exercise is associated with reduced anxious and depressive
symptoms in the population at large, but the association is not because of
causal effects of exercise."

