This supplementary information is presented as submitted by the corresponding author. It has not been copy-edited by NTvG.
Alcohol hallucinosis is a rare complication of chronic alcohol abuse, characterized by an acute onset of hallucinations during or after an episode of alcohol abuse. The hallucinations may persist for a long time, due to which the clinical picture can be mistaken for a schizophrenia spectrum disorder. The prognosis tends to be favourable, although especially untreated cases are associated with a considerable mortality risk.
A 38-year-old Surinamese-Hindustani male was admitted to a psychiatric hospital because of hallucinations with an acute onset during alcohol abuse which persisted for two months after abstinence. For the last two decades the patient used to drink whiskey in quantities of up to a litre per day, which repeatedly led to admissions in specialized rehabilitation centres. When admitted to our hospital he experienced hallucinations of insects swarming around him (zoopsia, visual hallucinations) and crawling upon and beneath his skin (tactile and formicative hallucinations) as well as verbal auditory hallucinations. All the while he had an intact consciousness, attention, orientation, and higher cognitive functions. Somatic and neuroimaging research yielded no abnormalities. Treatment with quetiapine and - subsequently - flupentixol turned out to be ineffective. Eventually, the patient recovered partly upon treatment with haloperidol but discharged himself prematurely.
Whenever a patient presents with hallucinations during or after a period of alcohol abuse, the diagnosis alcohol hallucinosis needs to be considered. The diagnosis must be distinguished from delirium tremens and schizophrenia spectrum disorder because the treatment and prognosis are essentially different. The pathophysiology of alcohol hallucinosis is only partly understood. The gamma-amino-butyric-acid(GABA)-ergic pathways would seem to be involved, and neuroimaging studies also suggest an involvement of the thalamus and frontal lobes. Treatment involves abstinence from alcohol, supplementation of thiamine, and symptomatic treatment of the hallucinations with an antipsychotic. Evidence-based treatment guidelines are as yet unavailable, but case reports and modest case series show favourable outcomes with haloperidol, flupentixol and risperidone. In addition, valproic acid would seem to be effective and well tolerated. Pharmacotherapy frequently results in a complete remission of the hallucinations. In case of remission and abstinence from alcohol, further treatment is not required. However, especially untreated alcohol hallucinosis is associated with a mortality rate of 37% in eight years. This is mainly due to the elevated risk of suicide (especially in cases with comorbid depression or anxiety disorder) and somatic complications secondary to alcohol abuse.
This case description exemplifies the occurrence of an alcohol hallucinosis and aims to raise awareness of the existence of this neuropsychiatric disorder.