The National Institutes of Health (NIH) has launched a four-year study to determine the safety and effectiveness of St. John's wort, a common herbal supplement, and citalopram, a standard antidepressant, compared to placebo in a new approach to research on minor depression.

The trial is being conducted at three sites. A total of 300 participants with minor depression will be randomly assigned a standardized extract of St. John's wort (Hypericum perforatum), citalopram, or placebo in a twelve-week double-blind trial. Researchers will assess changes in patients' symptoms, functioning, and quality of life. Those who show no improvement will receive the active treatment they hadn't been assigned before, while patients with improved symptoms will take their assigned treatment for another 14 weeks for a total of 26 weeks.

The more than $4 million collaborative study is funded by the National Institute of Mental Health (NIMH), the National Center for Complementary and Alternative Medicine (NCCAM), and the Office of Dietary Supplements (ODS).

Minor depression is a common disorder that may impair a person's functioning and quality of life and is a serious risk factor for major depression. Yet it is underdiagnosed and undertreated. The study addresses a need for definitive data on therapy for this significant health problem. Patients with minor depression who seek treatment from family doctors are often treated with prescription antidepressants, if their mood disorder is diagnosed at all. Many people use St. John's wort without consulting a physician. This study will help determine how the herbal agent and the antidepressant fit in the overall management of the disorder.

Men and women age 18 to 85 who meet diagnostic criteria for minor depression are eligible to participate. They must have experienced depressive symptoms for at least 6 months but less than 2 years continuously without meeting criteria for a major depressive episode or dysthymia within the past year. Additional exclusionary criteria include other mental disorders, such as schizophrenia, bipolar disorder, anxiety and substance use disorders. Individuals with some active physical illnesses, such as cardiovascular, renal, respiratory, endocrine, neurological, or blood diseases also are not eligible for the study.

Minor depression affects about 7.5 per cent of Americans during their lifetime. Although there is broad knowledge about the scope of suffering and disability due to major depressive disorder, less is known about the day-to-day struggles faced by people with minor depression. Its symptoms are the same as those of major depression, though fewer in number and causing less impairment. They include:

-- Either a depressed mood most of the day, nearly every day

-- Or a markedly diminished interest or pleasure in daily activities

-- Plus two to four of the following symptoms:

Significant weight loss or gain, or decrease or increase in appetite
Disturbance in sleep pattern
Noticeable agitation or slowness
Fatigue or loss of energy
Inappropriate feelings of worthlessness or guilt
Diminished ability to concentrate, indecisiveness
Recurrent thoughts of death or suicide

-- Symptoms must last at least 6 months but less than 2 years continuously.