The passionflower vine is a native of the Western hemisphere, named
for symbolic connections drawn between its appearance and the
crucifixion of Jesus. Native North Americans used passionflower
primarily as a mild sedative. It quickly caught on as a folk remedy in
Europe and was thereafter adopted by professional herbalists as a
sedative and digestive aid.
In 1985, Germany's Commission E officially approved passionflower as a
treatment for "nervous unrest." The herb is considered to be a mildly
effective treatment for anxiety and insomnia, less potent than kava
and valerian, but nonetheless useful. Like melissa (lemon balm),
chamomile, and valerian, passionflower is also used for nervous
stomach.
However, there is only weak supporting scientific evidence that
passionflower works for these purposes. Preliminary double-blind,
comparative trials suggest that passionflower might be helpful for
anxiety9 and chemical dependency.10Animal studies suggest that
passionflower extracts can reduce agitation and prolong sleep.1,11-13
However, there have not been any double-blind, placebo-controlled
studies of passionflower reported. (For information on why these
studies are essential for showing a treatment effective, see Why Does
the Natural Pharmacist Rely on Double-Blind Studies?)
The active ingredients in passionflower are not known.
Anxiety
A 4-week double-blind study of 36 individuals with anxiety
(specifically, generalized anxiety disorder) compared passionflower to
the standard drug oxazepam.9 Oxazepam worked more quickly, but by the
end of the four week trial, both treatments proved equally effective.
Furthermore, passionflower showed a comparative advantage in terms of
side-effects: use of oxazepam was associated with more job-related
problems (such as, for example, daytime drowsiness). However, because
this study lacked a placebo group, it would be premature to conclude
from it that passionflower has been shown to be an effective treatment
for anxiety.
Chemical Dependency
A 14-day, double-blind trial enrolled 65 men addicted to opiate drugs,
and compared the effectiveness of passionflower combined with the drug
clonidine vs. clonidine alone.10 Clonidine is a drug widely used to
assist narcotic withdrawal. It effectively reduces physical symptoms
such as increased blood pressure. However, clonidine does not help
emotional symptoms such as drug craving, anxiety, irritability,
agitation and depression. These symptoms can be quite severe and often
cause enrollees in drug treatment programs to end participation. In
this 14 day study, the use of passionflower along with clonidine
significantly eased the emotional aspects of withdrawal as compared to
clonidine alone.
Safety Issues
Passionflower is on the FDA's GRAS (generally recognized as safe)
list.
The alkaloids harman and harmaline found in passionflower have been
found to act somewhat like the drugs known as MAO inhibitors and also
to stimulate the uterus,3,4 but whether whole passionflower has these
effects remains unknown. Passionflower might increase the action of
sedative medications.5,6,7 Finally, there are five case reports from
Norway of individuals becoming temporarily mentally impaired from a
combination herbal product containing passionflower.8 It is not clear
whether the other ingredients may have played a role.
Interactions You Should Know About
If you are taking sedative medications, passionflower might exaggerate
their effect.
References
1. Speroni E, Minghetti A. Neuropharmacological activity of extracts
from Passiflora incarnata.Planta Med. 1988;54:488–491.
2. Schulz V, Hansel R, Tyler VE. Rational Phytotherapy: A Physician’s
Guide to Herbal Medicine. 3rd ed. Berlin, Germany: Springer-Verlag;
1998:84.
3. Newall CA, Anderson LA, Phillipson JD. Herbal Medicines: A Guide
for Health-Care Professionals. London, England: Pharmaceutical Press;
1996:206.
4. Farnsworth NR, Bingel AS, Cordell GA, et al. Potential value of
plants as sources of new antifertility agents I. J Pharm Sci.
1975;64:535–598.
5. Speroni E, Billi R, Mercati V, et al. Sedative effects of crude
extract of Passiflora incarnata after oral administration. Phytother
Res. 1996;10:S92–S94.
6. Speroni E, Minghetti A. Neuropharmacological activity of extracts
from Passiflora incarnata.Planta Med. 1988;54:488–491.
