Herbal Drugs: Mental effects
Last modified: Sunday, 31. May 2009 - 4:01 pm
Many herbal drugs are believed to reduce anxiety and depression The PDR-HM lists 47 herbals used to manage anxiety disorders. Of these, St. John’s wort and kava (Piper methysticum) are popular in the United States, and although they are not proven medicines, preliminary evidence suggests they may be effective.
The active ingredient of St. John’s wort is a substance called hyperforin. Like other antidepressants, hyperforin appears to work by helping to restore the proper balance to brain chemistry. In particular, hyperforin helps restore the balance of certain neurotransmit-ters, or chemical messengers, in the brain. These neuro-transmitters include serotonin, norepinephrine, and dopamine.
Kava contains a substance called dihydrokavain, which is a mild sedative and pain reliever. Preliminary research shows that kava reduces nervous anxiety, tension, and agitation, although these effects usually take at least a week, and often a month or more, to set in. Although other anti-anxiety drugs such as benzodiazepines are more effective than kava, the herb does not seem to impair mental functioning or reaction times the way benzodiazepines do.
Some researchers suggest that perhaps the biggest mental effect induced by those herbals that are untested and unproven is the placebo effect: If people believe they are taking an effective medication, their attitude about their illness improves and they feel better, at least initially. In particular, the placebo effect can cause patients to report improvements in subjectively measured symptoms such as pain or depression. That is why many drug studies include a placebo group — patients who receive a dummy pill instead of the drug being tested. That way, researchers can compare the placebo group with the group receiving the drug and determine if the drug in question induces more than the placebo effect.