Paranoid delusions • ideas of reference • sleep problems • Dx?

Patients with late-onset schizophrenia often have paranoid or partition delusions and believe people or objects can permeate through barriers and access their home with malignant intent.

Patients with LOS typically do not exhibit negative symptoms because remodeling and myelination of neuronal circuitry matures by late adulthood, and thus becomes more resistant to impairment of motivational processes in the anterior cingulate gyrus.^4,5,6

LOS is characterized by paranoid personality with predominantly positive symptoms, likely due to disruptions in cortico-striato-pallido-thalamic circuitry that manifest in increased frequency and severity of acoustic, tactile, or olfactory hallucinations and persecutory delusions.^1,6,7 Patients with LOS often have paranoid or partition delusions and believe people or objects can permeate through barriers and access their home with malignant intent.⁸ The prevalence of delusions positively correlates with increased age at diagnosis.⁹ Patients with LOS also often develop comorbid schizoid or schizotypal personalities.⁸ In contrast, patients with EOS primarily present with disorganized behavior and speech; hallucinations; and delusions.

Other features of LOS include a high female:male ratio and symptomatic improvement with antipsychotics.^7,10 Studies show that the LOS ratio of women:men can range from 2.2:1 to 22.5:1, which could be explained by the effect of dopaminergic-modulating estrogen from different sex-specific aging brain patterns.^8,11,12 Finally, patients with LOS are less likely to seek care for sensory deficits than their age-equivalent counterparts.^8,10 Fortunately, many of the characteristics of LOS predict good prognosis: Patients are usually female, display positive symptoms, have acute onset of symptoms, and are married with social support.¹⁰

Diagnosing LOS

LOS can be challenging to diagnose because of its atypical presentation compared with EOS, relative rarity in the population, and its propensity to be confused with progressive Alzheimer disease/dementia, delusional disorder, and major depressive disorder with psychotic features.^3,6 Patients with no prior psychiatric history often do not have ready access to psychiatrists and depend on PCPs and other clinicians to identify mental health issues. A careful history, including familial involvement, utilization of the Montreal Cognitive Assessment (MoCA) test, and evaluation of environmental factors, are crucial to arriving at the proper diagnosis.

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