Use of herbal medications among 200 psychiatric outpatients: prevalence, patterns of use, and potential dangers☆

1. Introduction 

Herbal medicines are readily available and commonly used in the United States [1], [2]. As over the counter preparations, herbal medicines are generally considered safe by the general population, and are commonly used for the treatment of psychiatric symptoms [2], [3]. St John’s wort (Hypericum perforatum) is commonly taken to treat depression, kava kava (Piper methysticum) for anxiolysis, Valerian (usually Valeriana officialis) to improve sleep, and Ginkgo biloba to improve memory [1], [2].

Herbal preparations contain one or more biologically active components, each with a unique side effect profile. When used in a knowledgeable fashion by individuals trained in their appropriate use and obtained from reliable producers, herbs are relatively safe. However, there have been several reports of clinically significant interactions between herbs and medications [4]. The use of herbs concurrently with a prescribed medication is extremely common. A survey conducted in the US reported that among adults taking a prescribed medicine, 18.4% were also taking at least one herbal compound. In addition, among those who used alternative therapies, 61.5% had not discussed this with their physician [5]. With the above points in mind, we examined patterns of herb use among a population of psychiatric outpatients.

2. Materials and methods 

This was a retrospective chart analysis, conducted with the approval of the UCSD Human Research Protection Program, which did not use consented subjects. Information, provided by psychiatric outpatients regarding their use of herbs, was retrospectively reviewed and characterized. As part of their routine evaluation, patients at UCSD Outpatient Psychiatric Services were asked about their use of herbal medications. While several different psychiatrists provided mental health care services, all patients were interviewed regarding herb use by one of two clinicians, one physician and one nurse. These two clinicians used open-ended questions to inquire about patients’ current and past use of any herbal medications and their reasons for using herbs. Because they are the four most common herbs used to treat psychiatric symptoms [1], use of kava, St. John’s wort, Ginkgo biloba, and valerian was specifically inquired about. The charts and initial evaluations of 205 consecutive patients, who were evaluated between 11/1/00 and 1/31/01, were retrospectively reviewed. Two hundred out of two hundred five patients provided information regarding their herb use. Five provided no information. Information from 200 patients regarding herb use was included in this analysis.

Each of the 200 patients was separated into one of three categories. Current users were those individuals currently taking herbs and nonusers had never taken herbal medication. The third category was made up of previous users who had taken herbs at any time in the remote or recent past, but were not currently using herbal products. χ2 was used to examine potential differences in the rate of herb use across genders and between age groups.

Reasons why current users were taking herbal medicines were also investigated. Patients were first asked, in an open-ended fashion, their reasons for using herbs. They were then asked to indicate which one of the following three choices best described why they were taking herbs: to improve overall mental health, to improve overall physical health, or other reasons. The number of patients who chose each of the three reasons was noted.

Additionally, two specific “high risk” patient groups were identified and the number of patients in each group noted. First were patients simultaneously taking benzodiazepines while taking valerian or kava, as they may be at risk for combined sedative effects, delirium, and coma [6]. The second group consisted of patients concurrently taking selective serotonin reuptake inhibitors (SSRIs) and St. John’s wort, a population at theoretical risk of serotonin syndrome. Although St. John’s wort possesses low SSRI activity, there are case reports of serotonin syndrome with the combination of St. John’s wort and an SSRI [7].

3. Results 

Of the 200 patients, 106 (53%) were female and 94 (47%) male. Twenty-nine (15%) were current users, 94 (47%) previous users, and 77 (38%) nonusers. Among current users; 17 (59%) took herbal products to improve overall mental health, 7 (24%) took herbs to improve overall physical health, and five (17%) indicated other reasons for taking herbs (such as prevention of a future illness). Of the 29 current users, 19 (66%) were age 21–50, 10 (44%) were age 51 or older, 17 (59%) were male, and 12 (41%) female. Current use was similar in males and females (Table 1), . and in patients of different ages (Table 2). .

Table 1.

			Gender
			Male	Female
	Herb Use	Yes	17	12
		No	77	94

Chi-Square = 1.33 p = 0.25

Table 2.

			Age
			21–50	>50
	Herb Use	Yes	19	10
		No	85	86

Chi-Square = 1.89 p = 0.17

Ten individuals reported current use of Gingko biloba, seven of valerian, seven of echinacea, five of ginseng, four of kava, and three of St. John’s wort. Seven subjects reported current use of more than one herbal medicine.

Two patients taking Saint John’s wort in combination with SSRI’s were identified. An additional two patients were taking kava in combination with a benzodiazepine. In none of the current users’ charts, including “high risk” patients, was there evidence that prescribing physicians were aware that patients were taking herbs.

4. Discussion 

Herbs are used for a variety of conditions, and prior studies indicate that one-third to one-half of all Americans has used herbs. We report similar results among a population of psychiatric outpatients. Specifically, almost two-thirds of surveyed patients reported they had taken or were currently using herbal remedies. Current use of herbal medications was not specific to any gender or age group.

Among a population of psychiatric outpatients, it is not surprising that most patients reported using herbs for the treatment of psychiatric symptoms. With the above points in mind, it is recommended that psychiatrists ask all patients, regardless of age or gender, about their use of herbs, and educate them about potential side effects and drug-herb interactions.

It is a commonly held belief that natural remedies, such as herbs, are safer alternatives to commonly used psychotropics. However, herbs have potentially serious adverse reactions of their own, including the risk of bleeding with Ginkgo [9], and hepatotoxicity with valerian [10]. Also, there is literature describing potentially life-threatening events related to drug-herb interactions. Rejection of a transplanted heart has been reported in a patient taking St John’s wort and cyclosporin. Presumably, St. John’s wort increased metabolism of cyclosporin via induction of the CYP3A isoenzyme [8].

The authors found no evidence in any current user’s chart that the treating physician was aware of their patient’s herb use. However, it is important to consider that we did not specifically interview patients and their doctors on this point, and it is possible that physicians were more aware of their patients’ herb use than is evident by our retrospective chart review. Still, it is worrisome that at least some physicians did not document patient education regarding herb use and potential side effects because they were unaware that their patients were using herbs.

In addition to educating patients about the potential side effects of herbs, it is important for clinicians to warn their patients about potentially dangerous drug-herb combinations. The additive effects of alprazolam and kava have produced coma in one reported case [6], and serotonin syndrome has been reported in patients taking St. John’s wort in combination with other antidepressants [7]. We identified four patients taking potentially dangerous drug-herb combinations. For none of these patients, was there evidence that treating physicians were aware that these patients were taking herbs. Again, despite the relatively low number of high-risk patients, the apparent lack of lack of patient education, regarding potentially serious drug-herb interactions, is concerning.

Previous reports have reviewed the demographics of herb use and described potential drug-herb interactions. To our knowledge, this is the first study to address this issue among a population of psychiatric outpatients. Although limited, our findings may help guide outpatient psychiatrists in terms of educating their patients about herbal medications. In future studies, these findings should be expanded and replicated across a variety of patient populations. A second limitation concerns the group of previous users. Unfortunately, the authors did not have information regarding when previous users had taken herbal medications. This information would have been a useful addition to this report. A third limitation is the lack of information about potential patterns of herb use associated with specific psychiatric diagnoses. For example, are patients with a particular psychiatric diagnosis more likely to be using certain herbs? Alternatively, are they more likely to be taking dangerous drug-herb combinations? These important issues should be addressed in subsequent studies. Finally, the retrospective design of the current study is a limitation. As previously mentioned, there is the possibility that patients under-reported their use of herbs. In fact, previous studies have documented patients’ reluctance to reveal their use of herbal supplements. However, in the current study, a standardized procedure for data collection was used that we believe may have lessened the difference between patients’ actual and reported use of herbs. In any case, this study underscores the need for psychiatrists to ask all patients about their use of herbs and to provide education regarding the efficacy, adverse effects, and potential drug-herb interactions of these products.