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Herbal Medicines and Phytochemicals May Improve Symptoms of Obsessive-Compulsive Disorder: Systematic Review
Date 01-15-2021
HC# 052053-656
Keywords:
Herbal Preparations/Phytochemicals
Obsessive-Compulsive Disorder (OCD)
Systematic Review

Ayati Z, Sarris J, Chang D, Emami SA, Rahimi R. Herbal medicines and phytochemicals for obsessive-compulsive disorder. Phytother Res. August 2020;34(8):1889-1901. doi: 10.1002/ptr.6656.

Obsessive–compulsive disorder (OCD) is the fourth most common mental health condition. It is characterized by uncontrollable, distressing, and recurrent thoughts, impulses, or images, and repetitive behaviors or mental acts that are carried out in attempt to reduce distress. Cognitive behavioral therapy is not always effective; thus, many patients are treated with selective serotonin reuptake inhibitors (SSRIs). These pharmaceuticals are not always effective and have unwanted side effects. The purpose of this study was to systematically review herbal therapies and phytochemicals used to treat OCD.

The following databases were searched from inception through June 12, 2019: PubMed, Scopus, and The Cochrane Library. The search terms were as follows: (“obsessive compulsive disorder” or “obsessive” or “obsessive compulsive”) and (“herbal medicine” or “herbal” or “traditional” or “plant” or “phytomedicine” or “complementary”). Excluded studies were duplicates, reviews, studies of obsessions other than OCD, or assessed non-plant–based complementary medicine. Only English studies were included. Included studies could be preclinical or clinical. Reference lists from included articles were hand searched for additional articles.

A total of 1022 articles were located, and 18 articles (11 in vivo studies and seven clinical studies) were included in this review. Of the seven clinical studies, five were conducted in Iran, and two were conducted in the United States. All of the clinical studies used the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) to assess OCD. Nine of the 11 in vivo studies used the marble-burying model to assess obsessive–compulsive behaviors.

Winter melon (Benincasa hispida, Cucurbitaceae) fruit

  • One study concluded that winter melon fruit extract had an anticompulsive effect in a mouse model of OCD without adversely affecting motor behavior.
  • The exact mechanism of action of melon fruit extract on OCD has not been established, but the mechanism may be similar that of SSRIs.
  • According to the authors, there are no clinical studies evaluating the effect of winter melon on OCD.

Cannabis (Cannabis sativa, Cannabaceae) and Cannabidiol (CBD)

  • One study concluded that CBD had an anticompulsive effect in a mouse model of OCD.
  • The mechanism of the OCD effect does not involve serotonin.
  • According to the authors, there are no clinical studies evaluating the effect of CBD on OCD.

Bitter orange (Citrus × aurantium, Rutaceae) fruit

  • One study concluded that bitter orange fruit essential oil given orally had an anticompulsive effect in a mouse model of OCD.
  • The main compound of the essential oil was limonene (97.83%), which is bioactive in the central nervous system and may enhance serotonergic pathways.
  • According to the authors, there are no clinical studies evaluating the effect of bitter orange fruit essential oil on OCD.

Butterfly pea (Clitoria ternatea, Fabaceae) aerial parts

  • One study concluded that butterfly pea extract had an anticompulsive effect in a mouse model of OCD, which was comparable to the pharmaceutical fluoxetine. Also, butterfly pea extract could potentiate the effect of a reduced dose of fluoxetine.
  • The exact mechanism of action of butterfly pea extract on symptoms of OCD has not been established, but the mechanism may involve serotonergic pathways.
  • According to the authors, there are no clinical studies evaluating the effect of butterfly pea aerial parts extract on OCD.

Taro (Colocasia esculenta syn. Arum colocasia, Araceae) leaves

  • One study concluded that taro extract had an anticompulsive effect in a mouse model of OCD, which was comparable to the pharmaceutical fluoxetine.
  • The exact mechanism of action of taro extract on symptoms of OCD has not been established, but the mechanism may involve serotonergic pathways.
  • According to the authors, there are no clinical studies evaluating the effect of taro leaf extract on OCD.

Saffron (Crocus sativus, Iridaceae) dried stigmata

  • A randomized, double-blind study treated participants with mild to moderate OCD (n = 50) with 30 mg/day saffron or 100 mg/day fluvoxamine for 10 weeks. Both groups similarly improved symptoms of OCD, with 34.7% of the saffron group and 30.4% of the fluvoxamine having a complete response. There was no significant difference between groups in adverse events (AEs).
  • Crocin is an active component of saffron. In a rat model of OCD, crocin had an anticompulsive effect.
  • The exact mechanism of action of saffron dried stigmata on symptoms of OCD has not been established, but the mechanism may inhibition of serotonin reuptake.

Curcumin from turmeric (Curcuma longa, Zingiberaceae) rhizome

  • One study concluded that curcumin had an anticompulsive effect in a rat model of OCD, and serotonin levels were increased and dopamine levels were decreased in the curcumin-treated rats.
  • According to the authors, there are no clinical studies evaluating the effect of curcumin on OCD.

Red feathers (Echium amoenum, Boraginaceae) flower

  • A randomized, double-blind, placebo-controlled study treated participants with OCD (n = 44) with 500 mg/day red feathers aqueous extract or placebo for six weeks. The red feathers group had significant improvement of symptoms of OCD (P = 0.035) and anxiety (P < 0.05) compared with placebo. There were no significant AEs associated with red feathers.
  • The mechanism of action of red feathers on improving symptoms of OCD may be related to the increase of dopamine and serotonin.

St. John’s wort (SJW; Hypericum perforatum, Hypericaceae) aerial parts

  • A randomized, double-blind, placebo-controlled, multicenter study treated participants with OCD (n = 60) with 600-1800 mg/day (flexible dose schedule) SJW or placebo for 12 weeks. There were no significant differences between groups in ameliorating the symptoms of OCD.
  • An open-label study treated participants with OCD (n = 12) with 900 mg/day SJW for 12 weeks. There was a significant improvement in symptoms of OCD (P = 0.001). Diarrhea and restless sleep were the most commonly reported AEs.
  • One in vivo study concluded that acute treatment with SJW had an anticompulsive effect in a mouse model of OCD; however, the effect was not maintained with chronic treatment.
  • The mechanism of SJW on improving symptoms of OCD may be related to SJW’s effect on serotonin, dopamine, gamma aminobutyric acid (GABA), norepinephrine, and L-glutamate.

Calabash gourd; bottle gourd (Lagenaria siceraria, Cucurbitaceae) fruit

  • One in vivo study concluded that treatment with calabash gourd methanolic extract had an anticompulsive effect comparable to fluoxetine in a mouse model of OCD.
  • Calabash gourd is an adaptogen.
  • According to the authors, there are no clinical studies evaluating the effect of calabash gourd on OCD.

Silymarin extracted from milk thistle (Silybum marianum, Asteraceae) leaf

  • A randomized, double-blind, controlled, pilot study treated participants with OCD (n = 35) with 600 mg/day milk thistle leaf methanol extract or 30 mg/day fluoxetine for eight weeks. Milk thistle significantly improved symptoms of OCD (P = 0.001), and there were no significant differences between groups in ameliorating the symptoms of OCD. However, the authors state that the sample size was small, and the extract was not standardized; thus, more research is needed.
  • The mechanism of action of silymarin on improving symptoms of OCD may be related to it enhancing serotonin activity, and inhibiting monoamine oxidase activity.

Crape jasmine; pinwheel flower (Tabernaemontana divaricata, Apocynaceae) leaf

  • One in vivo study concluded that treatment with crape jasmine leaf ethanol extract had an anticompulsive effect comparable to fluoxetine in a mouse model of OCD.
  • The mechanism may involve serotonergic pathways.
  • According to the authors, there are no clinical studies evaluating the effect crape jasmine on OCD.

Valerian (Valeriana officinalis, Valerianaceae) root extract

  • A randomized, double-blind, placebo-controlled study treated participants with OCD (n = 31) with 765 mg/day valerian root extract or placebo for eight weeks. Valerian rapidly and significantly improved symptoms of OCD compared with placebo (P < 0.001). The frequency of AEs was not significantly different between groups.
  • The mechanism of valerian on improving symptoms of OCD may be attributed to inhibiting GABA reuptake and serotonin binding.

Ashwagandha (Withania somnifera, Solanaceae) root extract

  • A randomized, double-blind, placebo-controlled study treated participants with OCD plus with or without anxiety disorder and taking SSRIs (n = 30) with 120 mg/day ashwagandha extract or placebo for six weeks. Ashwagandha significantly improved symptoms of OCD compared with placebo (P < 0.001) in participants with or without anxiety disorder. However, there were only 15 patients per group.
  • The mechanism of action as related to OCD is not reported.

According to the authors, this is the most comprehensive systematic review of herbal medicines and phytochemicals to treat OCD published since 2011. The results demonstrate that more well-designed clinical trials are needed for all potential herbal therapeutics intended to treat symptoms of OCD. The authors declare no conflicts of interest.

—Heather S. Oliff, PhD