Source: New Zealand Herald
Date: 2010-06-02
Author: Martin Johnston

Smoking may cause an increased risk of depression, according to a
New Zealand study which has followed 1200 people since they were
born in 1977.

Smoking and major depression have long been known to be linked.

But which is the primary cause has been unclear, and it is
possible that they reinforce each other.

Studies have suggested that some people who have depression smoke
as a form of self-medication.

Researchers from Otago University at Christchurch, led by
Professor David Ferguson, analysed data collected when
participants in their study were in the late teens to mid-20s.

They concluded it is probably smoking that increases the risk of
suffering symptoms of major depression, rather than the reverse.