Relationship between Psychiatric Illness, Cognitive Impairment and Physical Comorbidities in Older Adults: A Transdiagnostic Case-Control Study

Abstract

Introduction:

Cognitive impairment in older adults are often underdiagnosed, especially in the population with co-existing psychiatric illnesses. They can often be overshadowed by more apparent physical and psychiatric impairments, reflecting a need for more comprehensive evaluation in geriatric settings. This study examines the cognitive function and physical comorbidities among elderly patients (aged 65 and older) with clinically diagnosed psychiatric illness.  

Method:

A transdiagnostic case-control study of mentally ill elderly patients (n = 981) compared to controls (n = 63) was conducted. Patient data were obtained from the psychogeriatric day hospital while controls were recruited from local community centers. The patients were classified according to 4 categories based on their clinical diagnosis:

1. Mood Disorders e.g. Adjustment Disorder, Depression and Generalized Anxiety Disorder


2. Psychotic Disorder


3. Sleep Disorder


4. Neurocognitive Disorders e.g. Dementia and Mild Cognitive Impairment

Potential confounding variables, including age and education, were taken into account and an ANCOVA test shows no significant effect on results. 

Results:

1. A One-Way Analysis of Variance (ANOVA) demonstrated a significant difference in Montreal Cognitive Assessment (MoCA) test scores between older adults with mood, psychotic, and sleep disorders and those without (F(5, 701) = 11.550, p <.001), indicating an association between these psychiatric conditions and reduced cognitive function. 


2. Another One-Way Analysis of Variance (ANOVA) revealed that the Cumulative Illness Rating Scale (CIRS) scores were significantly higher in older adults with psychiatric and neurodegenerative conditions compared to those without (F(7, 1036) = 4.056, p <.001), suggesting a correlation between psychiatric illnesses and physical comorbidities.

Conclusion: 

Findings reveal significant association of psychiatric illnesses and lower cognitive functions, as well as heightened physical comorbidities. These results emphasize the need for more thorough assessment and tailored interventions to better address cognitive impairment amongst the geriatric population with psychiatric illnesses.