Medicinal plants for obsessive-compulsive disorder: A review of phytotherapeutic approaches

Background: Obsessive-compulsive disorder (OCD) is a chronic psychiatric condition characterized by intrusive thoughts and repetitive behaviors that impair functioning. Although selective serotonin reuptake inhibitors (SSRIs) and cognitive behavioral therapy are first-line treatments, 40–60% of patients achieve only partial remission, with persistent symptoms and adverse effects. This highlights the need for alternative approaches such as phytotherapy, which has shown potential neuroprotective and neurotransmitter-modulating properties. Methods: A structured narrative review with a systematic search was conducted across PubMed, Scopus, Web of Science, and Google Scholar up to April 2025. Studies evaluating medicinal plants or phytochemicals in OCD or OCD-like behavior were included. Both preclinical in vivo and human studies were assessed. A total of 26 studies (14 preclinical, 12 clinical) were included and appraised using a multi-domain quality framework and evidence hierarchy. Results: Preclinical studies indicated that several plant-derived compounds influence serotonergic, dopaminergic, and GABAergic systems and reduce OCD-like behaviors. However, most relied on non-specific models such as marble-burying, limiting interpretability. Clinical evidence was limited, with few randomized controlled trials and several low-quality or observational studies. While some interventions showed symptom improvement, methodological weaknesses and small sample sizes reduced reliability. Discussion: Current evidence does not support clinical recommendations for phytotherapy in OCD. Findings remain preliminary and hypothesis-generating. Future research should focus on well-designed clinical trials, standardized formulations, and translationally valid models to establish efficacy and safety.