Passion flower (Passiflora incarnata) was used traditionally in the Americas and later in Europe as a calming herb for anxiety, insomnia, seizures, and hysteria. It is still used today to treat anxiety and insomnia. Scientists believe passionflower works by increasing levels of a chemical called gamma aminobutyric acid (GABA) in the brain. GABA lowers the activity of some brain cells, making you feel more relaxed.
Anxiety Disorders
Research has shown that passion flower has the ability to markedly reduce the symptoms of anxiety disorders.
A trial at the Tehran University of Medical Sciences in Iran studied 36 individuals with generalized anxiety disorder to compare passion flower with the drug oxazepam, a medication used for anxiety. At the 4-week mark, both treatments proved equally effective. Moreover, passion flower showed a comparative advantage in terms of side effects because oxazepam can cause considerable impairment of job performance.
A second follow-up study by the same researches had the same findings; that passion flower was as effective as the drug oxazepam.
Insomnia
Herbalists consider passion flower an important herb for insomnia caused by mental worry, overwork, or nervous exhaustion. In the United Kingdom, passion flower is an ingredient in commonly-sold sedative preparations.
Passion flower has been used for minor sleep problems in both children and adults. It is an excellent sedative with no side effects.
Alcohol and Drug Withdrawal
Research has shown that passion flower is useful in withdrawal from opiates, marijuana, and alcohol.
Passion flower has sedative properties, and has been used as an aid to drug withdrawal. In one study, passion flower significantly reduced the symptoms of alcohol withdrawal and associated anxiety in mice.
A 14-day double-blind trial of 65 men addicted to opiate drugs found that passion flower combined with the drug clonidine was more effective in helping withdrawal than was clonidine alone.