Smith-Magenis Syndrome (SMS) is a neurogenetic disorder caused by deletions on chromosome 17p11.2 or mutations in the RAI1 gene. It is characterized by intellectual disability, behavioral disturbances like aggression, impulsivity, self-injury, and sleep disruptions. A hallmark feature of SMS is inverted melatonin production, leading to daytime sleepiness and nighttime insomnia, which exacerbate behaviors. Traditional treatments, such as antipsychotics and SSRIs, often show limited effectiveness and can cause side effects, including metabolic syndrome, sedation, and extrapyramidal symptoms.

Lithium has emerged as a promising alternative to manage treatment-resistant behaviors in SMS. Known for its mood-stabilizing properties in bipolar disorder, lithium modulates dopamine and serotonin, reduces aggression, and promotes neuronal plasticity. However, lithium requires close monitoring due to the risks of nephrotoxicity, thyroid dysfunction, and its narrow therapeutic index.

This study explores lithium’s role in managing severe behavioral disturbances in SMS, especially in patients unresponsive to conventional treatments. The objectives are: (1) to review the literature on lithium’s efficacy and safety in SMS and similar neurodevelopmental disorders, and (2) to present a clinical case of a 25-year-old SMS patient treated successfully with lithium after antipsychotics and SSRIs failed.

A literature review was conducted using PubMed and Web of Science, focusing on articles published between 2013 and 2023 on lithium in SMS and related disorders. Additionally, the clinical case of a 25-year-old male with SMS, exhibiting aggression and self-injury, was documented. After other treatments failed, lithium was introduced with regular monitoring of serum levels, renal, and thyroid function throughout six months.

Literature supports lithium’s efficacy in reducing aggression and impulsivity in SMS. Lithium modulates dopaminergic and serotonergic systems, stabilizing mood and reducing disruptive behaviors. In the clinical case, the patient improved within two weeks of lithium therapy. Over six months, aggression and self-injury diminished significantly, with no adverse effects and stable renal and thyroid function.

Lithium is an effective option for SMS patients with treatment-resistant behavioral disturbances, particularly aggression and self-injury. It offers a valuable alternative to antipsychotics and SSRIs, enhancing emotional stability and quality of life. However, careful monitoring is required to prevent toxicity. Further research is needed to confirm lithium’s long-term safety and efficacy in SMS.

None Declared