Letter to the Editor Complex hallucinations induced by lamotrigine Lamotrigine is an antiepileptic drug with large-spectrum efficacy in several forms of partial and generalized epilepsy and is also known as a mood-stabilizing medication used in bipolar disorder. The most described side effect of lamotrigine is allergy. Psychiatric manifestations are extremely rare reactions and only a few similar case reports are reported in the literature. We present a case of complex hallucinations with tactile and visual patterns induced by lamotrigine in an epileptic patient. Mrs. D.E. is a 73-year-old woman with a history of a stroke caused by atrial fibrillation, vascular epilepsy with generalized seizures treated recently by lamo- trigine. The first week after starting lamotrigine (25 mg once daily), Mrs. D. developed tactile hallucinations that increased with dose increase. She described sensations of ‘‘tiny insects coming out from her anus and crawling over her skin, and she had to close it with paper, otherwise, the insects spread all over her body, hair, clothes.’’ Her behaviour was exaggerated; she developed obsessive compulsive disorders (OCD) beha- viour with cleaning/washing compulsions and started to have a visual hallucinations (seeing strangers around the room). She has been seizure-free for 6 months. Electroencephalogram (EEG) during the psychotic episode was normal. Her tactile and visual hallucinations caused significant anxiety to her and mandated the switch to levetiracetam with reduction and withdrawal of lamotrigine, which led to the complete cessation of psychotic symptoms in 3 weeks. We initially discussed whether these symptoms should be considered as the side effects of lamotrigine. Otherwise, they may be an epileptic manifestation or onset of chronic psychiatric disease. Our patient had been seizure-free for at least 6 months before the onset of the psychotic episode, so we could not attribute it to post-ictal psychosis. Also, the time- sliced character of the beginning of hallucinations and its relationship with the introduction of lamotrigine led us to think of a toxic drug origin. Moreover, rapid remission of psychotic symptoms after dose reduction and withdrawal was observed. All these features lead to the conclusion that any hallucination, even minimal, maybe an uncommon adverse effect of lamotrigine, and thus its incrimination must be mentioned. We found this case interesting enough to share it, in order to participate in patient education about this rare but alarming side effect, to improve medication adherence and avoid unnecessary treatment. As found by other authors, hallucinations are atypical adverse effects of Lamotrigine, described by Weintraub [1] in a study of 546 patients with epilepsy, that reported 4.8% incidence of psychiatric and behavioural side effects with lamotrigine. A literature review by Villari et al. [2] documented acute psychotic episodes with lamotrigine in patients with or without a history of epilepsy [3–5] (Table 1). Even if its mechanism still not clear, we hypothesized that sodium channel blockade has a role in the generation of r e v u e n e u r o l o g i q u e x x x ( 2 0 1 8 ) x x x – x x x Table 1 – Literature review by Villari et al. [2] documented acute psychotic episodes with Lamotrigine in patients with or without a history of epilepsy [3–5]. Authors n Main behavioural manifestations Weintraub et al. [1] 546 (4,8%) Anxiety, behavioural change, depression, irritability/moodiness, or psychosis Villari et al. [2] (literature review) Desarkar and Sinha Savas et al. Margolese et al. Raskin et al. Brandt et al. Matsuo et al. Roberts et al. 1 2 1 2 6 216 (4) 1 Acute psychotic episodes, hallucinations and affective switching Affective switch Maniac episode Mood lability Agitation, mood change, delusions Paranoid thoughts, visual and auditory hallucinations, agitation and sleep disturbances Psychotic episode, delusion Visual hallucinations Brodie MJ et al.[3] 131 (6%) Insomnia, Irritability, anxiety, hypomania NEUROL-2046; No. of Pages 2 Please cite this article in press as: El Otmani H, et al. Complex hallucinations induced by lamotrigine. Revue neurologique (2019), https://doi.org/ 10.1016/j.neurol.2018.11.004 Available online at ScienceDirect www.sciencedirect.com