Leisure Time Exercise Might Not Affect Depression And Anxiety

Voluntary exercise does not appear to reduce anxiety and depression in
diverse populations, but exercise and mood could be associated through
a common confounding genetic factor, according to an article released
on August 4, 2008 in the Archives of General Psychiatry,
one of the JAMA/Archives journals.



Regular exercise has previously been associated with the reduction of
anxiety and depression. This has been concluded through experiments
with specific clinical populations, but a causal relationship has not
yet been established in the general population. Because there is the
possibility of a confounding factor that causes exercise and reduction
of symptoms to coincide, it is important to investigate the causal
relationship between the two.



To investigate this, Marleen H. M. De Moor, M.Sc., of VU University
Amsterdam, the Netherlands, and colleagues performed a twin study with
5,952 twins from the Netherlands Twin Register, 1,357 additional
siblings, and 1,249 parents. All participants were between the ages of
18 and 50. They were evaluated through surveys regarding leisure
exercise and through several scales to measure symptoms of anxiety and
depression.



After analysis, the authors found that the associations that were
observed between the symptoms and exercise were "small and were best
explained by common genetic factors with opposite
effects on exercise behavior and symptoms of anxiety and depression."
However, in observing the twins, "the twin who exercised more did not
display fewer anxious and depressive symptoms than the co-twin who
exercised less."



Notably, higher exercise levels of one twin were associated with lower
levels of depressive symptoms in the other twin. This was not displayed
in fraternal twins or in other siblings. Ultimately, it was shown that
individuals who increased their levels of exercise over time generally
did not display lessened anxious or depressive symptoms. All of these
points lead to a hypothesis that this association is somehow
genetically related. The authors comment: "It is unknown which genes
might be involved in voluntary exercise behavior and in the risk for
anxiety and depression." They suggest that the genes controlling the
neurological pathways processing dopamine, norepinephrine, opioids or
serotonin are potential areas for further investigation.



Ultimately, these results indicate that additional trials must be
performed before therapy using exercise can be legitimized. This does
not mean that exercise cannot benefit these patients. The authors note
that "Only voluntary leisure-time exercise is influenced by genetic
factors,
whereas the other type of exercise [directed and monitored by someone
else] is environment-driven. The absence of causal effects of voluntary
exercise on symptoms of anxiety and depression does not imply that
manipulation of exercise cannot be used to change such symptoms." They
indicate that different results may be obtained if this exercise is
delivered as a part of a therapy program. They say:В "The
antidepressant effects of exercise may only occur if the exercise is
monitored and part of a therapeutic program."



Testing Causality in the Association Between Regular Exercise
and Symptoms of Anxiety and Depression

Marleen H. M. De Moor; Dorret I. Boomsma; Janine H. Stubbe; Gonneke
Willemsen; Eco J. C. de Geus

Arch Gen Psychiatry. 2008;65(8):897-905.

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What is Anxiety?
For more information on what anxiety is and what to do about it, please see:
What is Anxiety? What Causes Anxiety? What To Do About It.



Written by Anna Sophia McKenney