Changes in Growth and Distribution of Hair Associated with Psychotropic Drug Use

In the 1997 review, it was found that psychotropic drugs can lead to various hair disorders, including hair loss and excessive hair growth. The drugs affect the mitotic rate of keratinocytes in the hair matrix, which can either stimulate or arrest hair growth. Specific drugs such as antipsychotics, antidepressants, lithium, carbamazepine, valproic acid, and vigabatrin have been linked to hair loss, while phenytoin and phenothiazines are associated with hypertrichosis. The evidence is particularly strong for hair loss with lithium and hypertrichosis with phenytoin. The review also notes that diagnosing drug-induced hair loss is challenging due to delayed effects and the potential for spontaneous hair loss. Lithium-induced hair loss can occur 1 to 54 months after treatment initiation, with regrowth possible 6 weeks after discontinuation. Carbamazepine was reported to cause hair loss in 6% of 240 epilepsy patients, while valproic acid has been associated with minor, transient hair loss. Phenytoin can cause both alopecia and hypertrichosis, with up to 34.9% of pediatric patients experiencing hypertrichosis in one study. The review emphasizes the importance of dermatological consultation before discontinuing a drug due to hair changes and the need for cautious and detailed reporting of drug-induced hair changes.