By PT Staff, published on March 1, 1994 - last reviewed on January 23, 2015
Kids share more than candy and germs when they're growing up.
Siblings of kids with emotional or behavioral problems tend to have those
same types of problems themselves.
Conduct problems and emotional disorders are especially likely to
run in families, according to Canadian psychiatrist Peter Szatmari, M.D.
Kids with attention deficit disorder need not necessarily have siblings
with similar problems, but it's very likely that these kids and their
sibs will have conduct problems or emotional disorders as well.
The findings suggest that nature and nurture are in cahoots once
again. Siblings may share a general genetic vulnerability for psychiatric
problems, while environmental factors determine which specific problems
The double whammy of environmental and genetic similarities within
families helps explain why conduct problems and emotional disorders
cluster with such high frequency.
Why not attention deficit disorders? Szatmari, of Chedoke-McMaster
Hospitals in Ontario, suspects that hyperactivity is purely genetic--and
not doubly triggered by the interplay of genes and family environment.
Kids may also "catch" problem behaviors from each other.
Szatmari studied over 1,000 randomly selected families, gathering
information on different psychiatric disorders from parents, teachers,
and children. Parents were most likely to report similar problems among
sibs. They may know their kids better than do teachers...or once a child
is tagged with a problem, they may be on the lookout for similar symptoms
For Szatmari, the implications are obvious. Treatment of mental
health problems should be aimed at entire families, not individuals. It
may work better and save money.