Release Date: May 16, 2005
ST. JOHN’S
WORT ONLY MINIMALLY EFFECTIVE IN RELIEVING MAJOR DEPRESSION, REVIEW
CONFIRMS
By David Crosson, Contributing Writer
Health Behavior News Service
St. John’s Wort, the
herbal medicinal long thought to relieve symptoms of depression,
provides only minor benefits in patients with
the most acute depression and perhaps no benefit for those with chronic
depression.
The updated review of 37
trials, involving 4,925 patients, reaffirms earlier findings that
St. John’s Wort:
--Reduces symptoms of mild-to-moderate depression among adults in
a manner similar to antidepressant drugs;
--Causes fewer side effects than some of the older antidepressants
on the market; and
--Causes slightly fewer side effects compared with selective serotonin
reuptake inhibitors, or SSRIs, the class of antidepressants most recently
developed.
The review was led by Professor
Klaus Linde of the Centre for Complementary Medicine Research at
Technical University in Munich, Germany. The reviewers
caution that “uncontrolled use of [St. John’s Wort] is
problematic because serious interactions can occur” with a number
of frequently used antidepressants and that physicians should regularly
ask their patients about their use of St. John’s Wort.
The National Center for
Complementary and Alternative Medicine, part of the National Institutes
of Health, holds that St. John’s Wort
is not a proven therapy for depression.
The review appears in the most recent issue of The Cochrane Library,
a publication of The Cochrane Collaboration, an international organization
that evaluates medical research. Systematic reviews draw evidence-based
conclusions about medical practice after considering both the content
and quality of existing medical trials on a topic.
All studies were double-blind,
randomized clinical trials involving patients with depressive disorders.
All involved comparisons between
St. John’s Wort and placebos or synthetic antidepressants given
for at least four weeks.
St. John’s Wort is
available over the counter in the United States, where lifetime depression
has an estimated prevalence of 16
percent.
In Europe, St. John’s Wort generally can be obtained only by
prescription and is used to treat anxiety and sleep disorders as well
as depression. St. John’s Wort has been subject to more trials
in Europe, especially in German-speaking countries, than in the United
States. However, because it is prescribed for a number of disorders
other than depression, Linde and colleagues included in their review
only those trials from German-speaking countries that were restricted
to patients with a diagnosis of major depression.
St. John’s Wort, scientifically referred to as hypericum extracts,
derives its name from the patron saint of nurses and Old English word
for “plant.” The mechanism by which it acts is unclear,
but St. John’s Wort is known to contain at least seven groups
of components that may contribute to its pharmacological effects. While
some of the components individually have been shown to have a positive
effect on some forms of depression, the total extract seems more clearly
beneficial.
Hypericum extracts are decidedly
less expensive than some of the most widely prescribed antidepressants,
such as Prozac. However, the composition
of St. John’s Wort depends on the raw plant material used, the
extraction process and the solvents used. As a consequence, the review
notes, “the amounts of bioactive constituents in different products
can vary enormously.”
Reviewers recommend that
St. John’s Wort products should be
avoided if they do not provide important content information, such
as the amount of total extract contained, the extraction fluid used
and the ratio of raw material to extract. They also call for more detailed
studies of the constituent components of St. John’s Wort.
Dr. John Williams, a professor
of medicine and psychiatry at Duke University who has studied St.
John’s Wort in the context of
depressed patients in primary care facilities, says the Linde review
has made him more cautious in his outlook on the product. Williams
says he currently feels St. John’s Wort should not be “a
first or second choice for U.S. patients with moderate to severe major
depression.” At the same time, he says, the product remains a “reasonable
option” for patients suffering from minor depression — as
long as they are able to locate “quality preparations.”
In their review, Linde and
colleague Michael Berner acknowledge potential conflicts of interest:
Linde, for once receiving travel expense reimbursements
from Schwabe, a manufacturer of St. John’s Wort; and Berner,
for a past research grant and travel expense reimbursement for speaking
at a meeting organized by Schwabe.
Linde K, et al. St John’s
Wort for depression (Review). The Cochrane Database of Systematic
Reviews 2005, Issue 2
The Cochrane Collaboration is an international nonprofit, independent
organization that produces and disseminates systematic reviews of health
care interventions and promotes the search for evidence in the form
of clinical trials and other studies of interventions. Visit http://www.cochrane.org for more information.
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