Psychosis Secondary to ALS in the Absence of Dementia: A Convincing Case

To the Editor: Psychiatric symptoms in amyotrophic lateral sclerosis (ALS) are thought to be restricted to cognitive and depressive symptoms.¹ However, early reports considered psychosis as a possible component of the disease.^2,3 Various cases have been reported, including a man requesting an amygdalectomy because of a somatic delusion.^4,5

We report on the case of 68-year-old man with ALS who acutely developed a bizarre somatic delusion in the absence of dementia. The debate regarding the “organicity” of the psychosis lead to delayed treatment and increased morbidity.

Case Report

The patient had an 18-month history of bulbar ALS, was communicating in writing because of anarthria, and was being treated with riluozole. In a long-term care facility, he acutely developed the belief that a person called “chief” was located in his throat and prevented him from drinking properly. He also believed that this person was the “key to finding the cure for ALS.” He was admitted because of repeated self-mutilation to his throat area using suction tubes and scissors in an effort to remove the “chief.” He was initially investigated in the neurology department. Other than the delusion, there were no new neuropsychiatric symptoms, and his level of consciousness was unimpaired. There was no evidence of delirium. A cerebral CT scan and a recent brain MRI were normal. The laboratory work-up was normal. A recent behavioral neurology assessment revealed only mild comprehension deficits. Consequently, the patient was transferred to the psychiatric emergency department because the symptoms were deemed to be “primarily psychiatric.” The psychiatric assessment revealed longstanding narcissistic and Cluster A personality traits, but no history of psychotic or mood disorder. There was no medication likely to have induced psychosis. Given the acute onset of a bizarre delusion at a late age and in the absence of previous psychiatric history, the diagnosis was psychotic disorder due to ALS.

During the debate around which service should be admitting the patient, he developed an aspiration pneumonia. He was then admitted to neurology for concurrent IV antibiotic and haloperidol 1 mg po hs treatments and discharged to his nursing home 5 weeks later. An outpatient neuropsychiatric assessment was performed less than 2 weeks after discharge because of similar self-mutilations. The somatic delusion was still present. Because of insomnia and increased psychomotor retardation with haloperidol, the treatment was changed to olanzapine 5 mg po hs, and eventually increased to 10 mg. The self-harm risk was reduced by behavioral measures, but the patient died in the following weeks from his progressing ALS.

Discussion

The acute onset of bizarre psychotic symptoms in the absence of past psychiatric history is an indication that these symptoms were most likely secondary to the ALS. Also, the content resembles a previous report of throat-related somatic delusion.⁴ This case highlights the rare but real occurrence of psychosis in ALS. The acute onset, course of illness, and nature of the delusions are important factors in the diagnostic assessment. More importantly, treatment plans should be based on the needs of the patient as opposed to theoretical debates about the “organicity” of the psychosis.