Influence of social cognition as a mediator between cognitive reserve and psychosocial functioning in patients with first episode psychosis

BACKGROUND

Social cognition has been associated with functional outcome in patients with first episode psychosis (FEP). Social cognition has also been associated with neurocognition and cognitive reserve. Although cognitive reserve, neurocognitive functioning, social cognition, and functional outcome are related, the direction of their associations is not clear. Therefore, the main aim of this study was to analyze the influence of social cognition as a mediator between cognitive reserve and cognitive domains on functioning in FEP both at baseline and at 2 years.

METHODS

The sample of the study was composed of 282 FEP patients followed up for 2 years. To analyze whether social cognition mediates the influence of cognitive reserve and cognitive domains on functioning, a path analysis was performed. The statistical significance of any mediation effects was evaluated by bootstrap analysis.

RESULTS

At baseline, as neither cognitive reserve nor the cognitive domains studied were related to functioning, the conditions for mediation were not satisfied. Nevertheless, at 2 years of follow-up, social cognition acted as a mediator between cognitive reserve and functioning. Likewise, social cognition was a mediator between verbal memory and functional outcome. The results of the bootstrap analysis confirmed these significant mediations (95% bootstrapped CI (-10.215 to -0.337) and (-4.731 to -0.605) respectively).

CONCLUSIONS

Cognitive reserve and neurocognition are related to functioning, and social cognition mediates in this relationship.

Staging cognitive impairment and incidence of dementia

AIMS

In a background of interest in staging models in psychiatry, we tested the validity of a simple staging model of cognitive impairment to predict incident dementia.

METHOD

A large community sample of adults aged ≥55 years (N = 4803) was assessed in the baseline of a longitudinal, four-wave epidemiological enquiry. A two-phase assessment was implemented in each wave, and the instruments used included the Mini-Mental Status Examination (MMSE); the History and Aetiology Schedule and the Geriatric Mental State-AGECAT. For the standardised degree of cognitive impairment Perneczky et al's MMSE criteria were applied. A panel of psychiatrists diagnosed cases of dementia according to DSM-IV criteria, and cases and sub-cases of dementia were excluded for the follow-up waves. Competing risk regression models, adjusted by potential confounders, were used to test the hypothesised association between MMSE levels and dementia risk.

RESULTS

Out of the 4057 participants followed up, 607 (14.9%) were classified as 'normal' (no cognitive impairment), 2672 (65.8%) as 'questionable' cognitive impairment, 732 (18.0%) had 'mild' cognitive impairment, 38 (0.9%) had 'moderate' cognitive impairment and eight (0.2%) had 'severe' impairment. Cognitive impairment was associated with risk of dementia, the risk increasing in parallel with the level of impairment (hazard ratio: 2.72, 4.78 and 8.38 in the 'questionable', 'mild' and 'moderate' level of cognitive impairment, respectively).

CONCLUSIONS

The documented gradient of increased risk of dementia associated with the severity level of cognitive impairment supports the validity of the simple staging model based on the MMSE assessment.

Conversion to dementia in mild cognitive impairment diagnosed with DSM-5 criteria and with Petersen's criteria

OBJECTIVE

In a background of revision of criteria for states of increased risk for progression to dementia, we compare the conversion rate to dementia and Alzheimer's disease (AD) of mild cognitive impairment (MCI) as diagnosed using DSM-5 (DSM-5-MCI) and Petersen's (P-MCI) criteria.

METHOD

A population representative cohort of 4057 dementia-free individuals 55+ years of age was followed up at 2.5 and 4.5 years in Zaragoza, Spain (ZARADEMP). Using the Geriatric Mental State- AGECAT for assessment, research psychiatrists diagnosed DSM-5-MCI and P-MCI following operationalized criteria. 'Conversion rate' (CR), 'annual conversion rate' (ACR), and incidence rate (IR) were calculated along with incidence rate ratio (IRR) to compare the performance of the intermediate cognitive definitions.

RESULTS

At 4.5-year follow-up, in individuals aged 65+ years, ACRs for non-cases, P-MCI, and DSM-5-MCI were 0.8, 1.9 and 3.4, respectively, for global dementia. The IRRs were 2.9 and 5.3 for P-MCI and DSM5-MCI, respectively, being the non-cases the reference category. The corresponding values were slightly lower for AD.

CONCLUSION

Conversion rate to dementia and AD was higher using DSM-5-MCI criteria than using Petersen's criteria. However, prediction of the construct still has some way to go, as most MCI individuals did not convert at 4.5-year follow-up.

Degree of cognitive impairment and mortality: a 17-year follow-up in a community study

BACKGROUND

To test the hypothesis that cognitive impairment in older adults is associated with all-cause mortality risk and the risk increases when the degree of cognitive impairment augments; and then, if this association is confirmed, to report the population-attributable fraction (PAF) of mortality due to cognitive impairment.

METHOD

A representative random community sample of individuals aged over 55 was interviewed, and 4557 subjects remaining alive at the end of the first year of follow-up were included in the analysis. Instruments used in the assessment included the Mini-Mental Status Examination (MMSE), the History and Aetiology Schedule (HAS) and the Geriatric Mental State (GMS)-AGECAT. For the standardised degree of cognitive impairment Perneczky et al's MMSE criteria were applied. Mortality information was obtained from the official population registry. Multivariate Cox proportional hazard models were used to test the association between MMSE degrees of cognitive impairment and mortality risk. We also estimated the PAF of mortality due to specific MMSE stages.

RESULTS

Cognitive impairment was associated with mortality risk, the risk increasing in parallel with the degree of cognitive impairment (Hazard ratio, HR: 1.18 in the 'mild' degree of impairment; HR: 1.29 in the 'moderate' degree; and HR: 2.08 in the 'severe' degree). The PAF of mortality due to severe cognitive impairment was 3.49%.

CONCLUSIONS

A gradient of increased mortality-risk associated with severity of cognitive impairment was observed. The results support the claim that routine assessment of cognitive function in older adults should be considered in clinical practice.

Mild cognitive impairment diagnosed with the new DSM-5 criteria: prevalence and associations with non-cognitive psychopathology

OBJECTIVE

To contrast the prevalence of mild cognitive impairment (MCI) as diagnosed using DSM-5 criteria (DSM5-MCI) with MCI as diagnosed using Petersen's criteria (P-MCI) and to explore the association of both with non-cognitive psychopathological symptoms (NCPS).

METHOD

A two-phase epidemiological screening was implemented in a population-based sample of individuals aged 55+ (n = 4803). The Geriatric Mental State (GMS) was the main psychopathological instrument used, and AGECAT was used to make psychiatric diagnoses. Research psychiatrists diagnosed DSM5-MCI and P-MCI using operational criteria. Logistic regression models were then used to investigate the association of MCI with anxiety and depression and with NCPS.

RESULTS

Weighted prevalence of DSM5-MCI and P-MCI was, respectively, 3.72% and 7.93% for the aged 65+. NCPS were common in both MCI categories, but negative-type symptoms such as 'anergia' and 'observed slowness' were considerably more frequent among persons with DSM5-MCI. Anxiety and depression diagnostic categories were associated with both P-MCI and DSM5-MCI, but affective-type symptoms were mainly associated with P-MCI. Some negative-type symptoms were inversely associated with P-MCI, and no association was observed with DSM5-MCI.

CONCLUSION

The prevalence of DSM5-MCI was half that of P-MCI. Negative-type NCPS were more frequently and typically associated with DSM5-MCI.

The prevalence of dementia and depression in the elderly community in a southern European population. The Zaragoza study

BACKGROUND

Provocative international disparities reported in the prevalence rates of dementia and depression require further investigation. This is the first psychiatric study, to the best of our knowledge, about the prevalence of DSM-III-R dementing and depressive disorders and their relationships in a representative, stratified community sample of the elderly in both a Spanish-speaking country and southern Europe.

METHODS

A two-stage screening was completed in 1080 elderly. Sampling with replacement was done, and the cumulative response rate was 88%. In phase 1, lay interviewers administered the Spanish versions of the Mini-Mental State examination and the Geriatric Mental State Schedule-Automated Geriatric Examination for Computer Assisted Taxonomy package. In phase 2, research psychiatrists administered the same instruments and the History and Aetiology Schedule to all the probable cases and a similar number of randomly selected, probably normal subjects.

RESULTS

An estimated 5.5% of the elderly were considered to have a dementing disorder, the most prevalent types being primary degenerative dementia, Alzheimer's type (4.3%), and multi-infarct dementia (0.6%). Depressive disorders were found in 4.8% of the elderly. Psychiatric morbidity, specifically depression, was associated with lower educational levels. "Case levels" of depression were documented in 25.4% of the demented cases and case levels of "organic" disturbance were seen in 18.2% of cases of major depression.

CONCLUSIONS

Among the elderly, the prevalence of Alzheimer's disease and multi-infarct dementia, as opposed to depression, increases steeply with age. The overlap found between dementia and depression may have nosological implications. There could be an effect of lower education levels on psychiatric morbidity, particularly on depression.