Delirium and depression: inter-relationship and clinical overlap in elderly people

Abstract

Delirium and depression are complex neuropsychiatric syndromes that are common in the elderly and associated with a variety of poor healthcare outcomes. Accurate detection is key to providing optimal care for these conditions but is complicated by their considerable clinical overlap. This includes shared symptom profiles as well as comorbidity. Careful assessment of symptom character as well as the context and course of disturbances can allow for more accurate diagnosis. Prior depressive illness is a common finding in patients with delirium, while depressive illness is a recognised sequel of delirium. Evidence points to similar pathophysiological mechanisms involving disturbances in stress and inflammatory responses, monoaminergic and melatonergic functions, that in turn point to avenues for therapeutic intervention. Development of better tools for systematic assessment for delirium and depression in populations at high risk by virtue of age, diminished cognitive reserve and frailty is a key target to achieve improved healthcare outcomes.

Activation of sigma-1 receptor chaperone in the treatment of neuropsychiatric diseases and its clinical implication

“…Delirium and depression are complex neuropsychiatric symptoms common in the elderly, and are associated with poor healthcare outcomes (20). The pathophysiology of delirium is still not clearly understood.…”

“…The pathophysiology of delirium is still not clearly understood. Accumulating evidence suggests that drug toxicity, inflammation and acute stress responses all contribute to the disruption of neurotransmitters, such as acetylcholine, glutamate, g-aminobutyric acid, dopamine, serotonin and norepinephrine, and consequently, to the development of delirium (20,21).…”

When psychiatric symptoms reflect medical conditions

“…Mental-state disturbance in medical inpatients is delirium until proved otherwise Psychiatric conditions tend to develop insidiously rather than over hours to days A full physical and neurological exam, basic cognitive assessment and routine 'psychiatric' blood screens should be undertaken in all patients presenting with new-onset psychiatric symptoms Cognitive assessment is fundamental to the identification of delirium and/or encephalopathy, with impairment in tests of sustained attention having particular sensitivity Limbic encephalitis, especially NMDA receptor antibody encephalitis, should be considered as a differential diagnosis in first presentations of psychosis KEYWORDS: psychiatry, delirium, encephalitis, psychosis, cognition, diagnosis ■ CME Acute medicine undetected, or lethargy and psychomotor retardation confused for the avolition and withdrawal of severe depression. 6 Misdiagnosis can be avoided if it is remembered that delirium is characterised by an abrupt onset, altered conscious level and fluctuating course, features that also distinguish it from dementia. Impaired attention, with associated disorientation, is the key clinical finding.…”

Delirium after thiazide diuretic suspension can unmask diabetes insipidus

“…Delirium is a common serious complication in hospitalized older people (the overall occurrence rates of delirium in these populations is 29-64%). 1,2 The regulation of water balance is governed by a feedback mechanism involving the hypothalamus, the neurohypophysis and the kidneys. When plasma osmolality increases to levels above a physiological threshold (290-295 mOsm/kg of water), there is increased secretion of AVP.…”