Sarah, a normally exuberant young woman, felt fatigued and out of sorts. For three weeks, she had dreaded getting out of bed in the morning and found little joy in her occupation as a physical education teacher at a California high school. She had lost ten pounds from her already lean frame, and she couldn’t work up an appetite. She went to bed worn out but awoke in the early morning hours, lying awake until the hazy dawn light peeked through her curtains.
Worried that she had a serious illness, Sarah made an appointment with her physician. After taking a history and doing a physical examination to rule out other illnesses, her doctor told Sarah that she was suffering from depression, and together they discussed treatment alternatives.
Sarah is among the estimated 23 percent of people living in developed countries who, at some point in their lifetime, experience the symptoms of the most common and most treatable form of depression. Symptoms include feelings of apathy, dejection, loss of appetite or overeating, and disrupted sleep patterns. (Bipolor or manic-depressive disorder is more rare, occurring in about 1 percent of the population). While it is difficult to pinpoint depression’s cause, it is generally believed to be linked to physiological factors such as hormonal or chemical imbalances. Sometimes outside factors, such as the death of a loved one or loss of a job, may trigger depression.
Depression is a major cause of work-related disability, use of medical services, and drug use. Last year in the United States, sales of Prozac totaled almost $1.5 billion, and those of a similar drug, Zoloft, reached nearly $1 billion. These and other modern antidepressant drugs are effective, and they usually have few side effects.
Many herbs have been used to treat mild depression over the years, but only one has been shown to relieve the symptoms of depression in clinical studies–St.-John’s-wort (Hypericum perforatum).
How antidepressants work
A deficiency of two neurotransmitters (chemical messengers that transmit signals in the brain), serotonin and norepinephrine, is associated with depression, according to some scientific evidence. Antidepressants correct this deficiency by increasing the body’s supply of serotonin and/or norepinephrine.
Synthetic antidepressants are of three types. Tricyclic antidepressants, so called because they contain three fused rings in their chemical structure, increase the activity of norepinephrine; they include Imipramine, Desipramine, and Doxepin. Monoamine oxidase (MAO) inhibitors, such as Parnate, Nardil, and Marplan, increase the concentration of serotonin and epinephrine in storage sites in the central nervous system. Selective serotonin reuptake inhibitors, including Prozac, Zoloft, and Paxil, allow serotonin to accumulate in the space between the neurons, rather than being reabsorbed.
Side effects associated with synthetic antidepressants range from annoying ones, such as constipation and cotton mouth, to more serious problems such as impotence and irregular heart rhythm. Selective serotonin reuptake inhibitors have more limited side effects than the other categories of antidepressants: they include nausea, insomnia, headache, and abnormal weight loss or gain.
Clinical studies of St.-John’s-wort
Just how St.-John’s-wort fights depression has not been clearly demonstrated. Many St.-John’s-wort products available in Europe and the United States are standardized to hypericin, a constituent that some researchers believe inhibits MAO; however, other compounds may also be involved. However it works, St.-John’s-wort has proven effective in clinical studies.
Twenty-five controlled clinical studies completed prior to 1993 involved 1,592 people who took between 300 and 900 mg of an extract of St.-John’s-wort tops for two to sixteen weeks. Fifteen of the studies were placebo-controlled; the other ten compared preparations that contained St.-John’s-wort with preparations that did not. Unfortunately, many of the studies conducted between 1979 and 1989 included preparations containing both St.-John’s-wort and valerian, an herb that is often used as a mild sedative and sleep aid. Although the preparations were beneficial and produced few or no side effects, the mix made it impossible to attribute effects to one herb or the other. Credible clinical studies on St.-John’s-wort alone have occurred only recently.
In 1994, a randomized, placebo-controlled, double-blind study–the most rigorous kind of study–by a psychiatrist, an internist, and a general practitioner in Austria evaluated the effect of St.-John’s-wort on 105 outpatients diagnosed with mild to moderate depression or with temporary depressive moods. The patients received 300 mg of either St.-John’s-wort extract (standardized to 0.9 mg hypericin) or a placebo three times a day for four weeks. Sixty-seven percent of those taking St.-John’s-wort and 28 percent of those taking the placebo showed improvement. Those taking the extract felt significantly less sad, hopeless, helpless, and useless, were less fearful, and slept better. Side effects, compared with those caused by synthetic antidepressants, were of minor significance. The authors deemed St.-John’s-wort to be safe and effective for mild to moderate forms of depression. However, they cautioned that it is not suitable for more serious conditions such as manic-depressive disorder.
Generally speaking, the results of one study only point to the need for more studies. The safety and effectiveness of a substance are not confirmed until well-designed studies have been repeated with a large number of subjects and with similar outcomes.
In 1995, a researcher at the University of Exeter in England evaluated eighteen clinical studies of St.-John’s-wort preparations used to treat depression, fourteen using a placebo for comparison and four using standard antidepressive drugs. He found that eight of the placebo-controlled studies and three of the others met acceptable standards of research design. He then evaluated the studies, concluding that St.-John’s-wort extract was superior to a placebo and as effective as standard medications in alleviating symptoms of depression, with fewer adverse reactions than standard medications.
St.-John’s-wort should not be mixed with synthetic antidepressants. Because it may inhibit MAO, taking it with selective serotonin reuptake inhibitors such as Prozac could cause serious health damage.
Additionally, although side effects have not been reported in the clinical studies, range animals eating the plant and then standing in bright sunlight have experienced sunburn or blindness from photosensitization.
Depression is a condition that requires professional medical diagnosis and treatment. If you are taking or contemplating taking St.-John’s-wort, this treatment option should be discussed with your health-care provider, especially if he or she has prescribed other drug therapies.
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