Nutraceutical, Nutritional and Phytotherapeutic Interventions for Neuropsychiatric Disorders Associated with Intellectual Disability: Mechanisms and Clinical Evidence

Intellectual disability (ID) is frequently accompanied by a range of neuropsychiatric and neurological comorbidities, including anxiety, depression, autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), sleep disturbances, and epilepsy. Conventional pharmacological treatments often provide partial relief and may be associated with adverse effects, prompting interest in adjunctive strategies such as phytotherapy. This review examines the current evidence on selected plant-derived compounds—particularly Crocus sativus (saffron), Bacopa monnieri, Curcuma longa (curcumin), and other botanicals—in the management of disorders associated with ID. Mechanistic pathways, clinical evidence, and safety considerations are critically discussed. Although some phytotherapeutic interventions have shown preliminary evidence of potential benefit and may modulate pathways involving neuroinflammation, oxidative stress, and neurotransmitter function, direct clinical evidence in individuals with ID remains limited. Further well-designed randomized controlled trials, particularly in ID-specific populations, are needed to establish efficacy, safety, optimal dosing, and clinical applicability.