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August 6, 1999
It costs hundreds of millions of dollars for pharmaceutical companies to bring a new drug to market, but if you ask National Institute of Mental Health (NIMH) psycho-pharmacologist Jerry Cott, Ph.D., you might think that some remedies grow on trees-and other plants.
Cott, chief of the NIMH's adult psychopharmacology research program, is currently on loan to the National Center for Complementary and Alternative Medicine (NCCAM) of the National Institutes of Health. He spoke to a receptive audience at an APA annual meeting symposium in Washington, D.C., in May on alternative therapies for anxiety and depression.
Cott is unabashedly enthusiastic about the therapeutic potential of whole-plant extracts and other natural remedies. He believes that conventional psychopharmacology has become fixated on the idea that it is always best to try and isolate a single, active compound for use as a therapeutic agent. This philosophy, according to Cott, ignores the potential for biological synergy that may exist in a whole-plant extract as opposed to an isolated compound.
"There's really very little new going on in the world of psychopharmacology," said Cott. "What we have primarily is incremental improvements of existing medications." Although newer antidepressants may have more favorable side-effect profiles than the older drugs, they are no more effective, he pointed out. Plants offer the potential for "some different compounds and some different approaches," he added.
Reserpine is an example of a psychiatric drug that is less effective and more toxic than the plant from which it is derived, rauwolfia, according to Cott. Rauwolfia was "the first antipsychotic," having been used in India for at least 2,000 years, he observed.
When Cott prepared a crude extract of the whole plant, he found that it bound to GABA-B receptors, to dopamine-2 receptors, and to alpha-2 adrenergic receptors, a binding profile markedly distinct from reserpine's.
This was clearly "not reserpine doing this, but whatever it is, it would clearly affect the antipsychotic activity of reserpine," he observed. "If you're using this plant as an antipsychotic, then something that binds to GABA and D2 and alpha-2 is surely going to be relevant to that pharmacology, but we've thrown it away when we use reserpine."
Similar results have been found with gingko, a tree whose extracted leaves have been used to enhance memory in patients with dementia. Efforts by French scientists to find a single compound in gingko that was more potent than the whole-plant extract have repeatedly failed, according to Cott.
"It was very frustrating because they even tried adding back the pure compounds in the same ratio that they occurred in the plant and found that it still was not as active as the crude extract," he noted. "So there's something going on here; whether it's synergism or what, we don't really understand the full picture. But there are so many instances where this is true, where there seems to be some kind of synergism-something extra that you get from a crude extract-that we really can't ignore it."
NCCAM has set aside $15 million for a trial to see if gingko can prevent the development of Alzheimer's dementia, Cott added.
The most exciting recent finding in psychiatry, according to Cott, involves neither plants nor single-compound drugs, but the dietary supplement omega-3 fatty acids. A study of 30 unstable bipolar patients on medication found that those given a daily supplement of omega-3 fatty acids (as fish oil capsules) experienced a dramatically longer period of remission than those given a placebo. The study was published in the May 1999 issue of Archives of General Psychiatry.
There is "quite a good correlation across countries" showing that the more fish the residents consume, the lower the incidence of depression," said Cott. There are also data suggesting that postpartum depression may be related to inadequate consumption of fatty acids during pregnancy, Cott added.
As with herbs, however, the understanding of how essential fatty acids work is poor. "There's no clear agreement on what's going on," said Cott. Lipid metabolism "is horrendously complicated," he added.