600 Complementary and Alternative Therapies
1994; Kanowski, Hermann, Stephan, Wierich, & Horr, 1996;
Le Bars et al., 1997; Wesnes et al., 1997) that met the authors•
standards for strong research methodology. These authors
concluded there to be a •small but signi“cant effectŽ of
ginkgo biloba extract on cognitive function, such as memory
and attention, in patients with Alzheimer•s disease (Oken
et al., 1998). Likewise, studies have found ginkgo biloba to
improve mild to moderate memory impairment in elderly
patients (Rai, Shovlin, & Wesnes, 1991), memory and psy-
chopathology (Hofferberth, 1994), as well as daily living and
social behavior (Le Bars et al., 1997). Moreover, consistent
with previous reviews, ginkgo biloba was found to have no
signi“cant adverse effects.
Ginseng
Ginseng, a popular herb in traditional Chinese medicine, is
primarily used for its effects on anxiety, concentration, and
physical stress. Yun (1996) found Panax ginsengC. A. Meyer
(Korean ginseng) to prevent the development of cancer in
mice by inhibiting the proliferation of tumors. He has also
demonstrated a decrease in the risk of certain types of cancer
in 1,987 pairs of humans when ginseng was ingested as a
fresh extract or powder, as well as a decrease in the relative
risk of cancer in a prospective population-based study of
4,634 adults. Ginseng has also demonstrated to improve
quality of life among healthy volunteers (Wiklund, Karlberg,
& Lund, 1994), as well as improve mood, vigor, well-being,
and psychomotor performance in patients with noninsulin-
dependent diabetes mellitus (Sotaniemi, Haapakoski, &
Rautio, 1995).
Several studies investigating the mechanism of action
through which ginseng works demonstrate antinociceptive
effects of ginseng on stress-induced mice (H.-S. Kim, Oh,
Rheu, & Kim, 1992; Takahashi, Tokuyama, & Kaneto, 1992).
Other studies suggest ginseng may enhance nitric oxide
synthesis (Gillis, 1997), promote cytokine induction (Sonoda
et al., 1998), or enhance natural killer cell activity in healthy
subjects and in patients with chronic fatigue and acquired im-
munologic syndromes (Gillis, 1997).
Kava
Kava, which means •bitterŽ in Polynesian, is derived from a
black pepper plant in the South Paci“c called Piper methys-
ticum, or •intoxicating pepper.Ž Kava has been traditionally
ingested as a drink, but recently sold in capsule form in health
food stores in the United States. Explorers• journals have
documented the effects of kava for centuries: Kava has a
numbing effect on the tongue when drunk, is tranquilizing
and relaxing, and has genitourinary antiseptic qualities
(Anonymous, 1988). However, too much kava can cause ad-
verse effects such as dermopathy (Norton & Ruze, 1994), a
skin condition characterized by scaly skin, gastrointestinal
distress, and sleepiness (Cerrato, 1998), or a semicomatose
state when it interacts with alprozam (Almeida & Grimsley,
1996).
There are few randomized trials investigating the ef“cacy
of kava on anxiety. The majority of trials that do exist are
published in German. These studies have found kava extract
to be superior to placebo and comparable to oxazepam and
bromazepam (Volz & Keiser, 1997). A randomized, placebo-
controlled study of 101 outpatients with various anxiety
disorders according to the Diagnostic and Statistical Manual
of Mental Disorders, 3rd Edition, Revised (DSM-III-R;
American Psychiatric Association, 1987) criteria also found
kava to be superior to placebo by reducing anxiety and caus-
ing fewer side effects (Volz & Keiser, 1997).
The psychopharmacology of kava remains unclear. Initial
hypotheses suggested by investigators include: (a) Kava in-
creases the number of binding sites of GABAAreceptors
(Jusso“e, Schmitz, & Hiemke, 1994); (b) it modulates
the serotonin-1A receptor activity (Walden, Von Wegerer,
Winter, & Berger, 1997; Walden, Von Wegerer, Winter,
Berger, & Grunze, 1997); (c) it serves as reversible MAO-B
inhibitors (Uebelhack, Franke, & Schewe, 1998); or (d) it in-
hibits NAchannels (Magura, Kopanitsa, Gleitz, Peters, &
Krishtal, 1997).St. Johns’WortSt. Johns• wort (SJW) is an herbal product resulting from the
”owering of the plant Hypericum perforatumL. The plant•s
oil has been used for centuries as a medicine to heal burns
and improve mood. Over the past two decades, the pharma-
ceutical industries have attempted to develop extracts of SJW
for more popular and standardized use. In Germany, SJW is
the most widely prescribed treatment for depression, totaling
more than 25% of prescribed antidepressants (Muller &
Kasper, 1997).
Overall, the research suggests SJW to be ef“cacious in re-
ducing depressive symptoms and to produce signi“cantly
fewer side effects as compared to popular antidepressants.
Studies comparing SJW to placebo have found antidepres-
sive ef“cacy as well as high tolerability for SJW among pa-
tients with mild depression (Hansgen, Vesper, & Plouch,
1994; Hubner, Lande, & Podzuweit, 1994; Sommer &
Harrer, 1994). SJW has also demonstrated to be as effective
as imipramine (Vorbach, Hubner, & Arnold, 1994), maproti-
line (Harrer, Hubner, & Podzuweit, 1994), and amitryptiline