A proof-of-concept study testing the factor structure of the Stop Signal Task: overlap with substance use and mental health symptoms.

Background: Research utilizing experimental tasks usually does not report estimates of internal reliability of measurement. However, modern measurement theories conceptualize reliability as sample dependent indicating that reliability should be empirically demonstrated in the samples used to make inferences.Objectives: Test whether confirmatory factor analytic (CFA) estimates of reliability can be applied to a commonly used task measuring response inhibition (the Stop Signal Task) to predict substance use (alcohol and cannabis) and mental health symptoms.Methods: Thirty-seven participants between the ages of 18-20 (72% female; 16% Asian, 3% Native American, 11% Black or African American, 59% White; 32% Latino/a/x) were recruited via social media advertisement and attended a laboratory visit. The Stop Signal Reaction Time (SSRT) was calculated as the outcome for three experimental blocks and used as indicators in a CFA.Results: CFA suggests the task yields reliable scores; factor loadings were statistically significant (p < .05) and substantial (standardized loadings ranged from .74 to .94). However, reliability increased across experimental blocks and error was non-trivial (ranging from 50% to 12% of the variance). The inhibition factor predicted higher maximum number of drinks consumed (ß = .37, p < .05), higher frequency of cannabis use (ß = .39, p < .05), and more cannabis use occasions within using days (ß = .40, p < .05), as well as facets of mental health (anxious/depression, attention, and anxiety problems; all p's < .05).Conclusion: Results support the utility of CFA to test for reliability of measurement, with the ability to inhibit dominant responses serving as a transdiagnostic correlate of substance use and mental health problems.

Neuropsychiatric symptoms in severe dementia: Associations with specific cognitive domains the Cache County Dementia Progression Study.

OBJECTIVES: To examine the prevalence of neuropsychiatric symptoms (NPS) and cognitive correlates in severe dementia. METHODS: A population-based sample of 56 individuals with severe dementia (85.7% Alzheimer's type; 67.9% female) were assessed with the Severe Cognitive Impairment Profile (SCIP) and the Neuropsychiatric Inventory (NPI). Descriptive statistics displayed the frequency of NPS and bivariate and multiple regression analyses examined the associations between cognitive domains on the SCIP and NPS total, domain, and cluster scores. RESULTS: NPS were common in severe dementia with 98% of the sample exhibiting at least one symptom. Most common were delusions, apathy, agitation/aggression, and aberrant motor behavior, affecting 50% or more of participants. SCIP comportment was significantly associated with NPI total score and apathy (r = -.350 and -.292, respectively). All SCIP domains except for arithmetic, visuospatial, comportment, and motor behavior were significantly associated with agitation/aggression (r = -.285 to -.350). These associations remained in individual multiple regression models. CONCLUSION: In severe dementia, impairment in specific cognitive domains was associated with more severe NPS. Environmental manipulations to reduce processing demands in persons with severe dementia may be a useful strategy to target agitation and aggressive behaviors.

Caregiver-Care Recipient Relationship Closeness is Associated With Neuropsychiatric Symptoms in Dementia.

OBJECTIVE: Closer caregiver-care recipient (CG-CR) relationships are associated with better cognitive and functional abilities, activities of daily living (in persons with dementia), and lower informal care costs. METHODS: Due to the difficulty in treating neuropsychiatric symptoms (NPSs) and their detrimental effects on caregivers and care recipients, we examined whether closeness of CG-CR relationships was associated with overall NPS severity or with specific NPS symptom domains in care recipients. In a longitudinal population-based study in Cache County, Utah, the 12-item Neuropsychiatric Inventory (NPI-12) was assessed in 300 CG-CR dyads. Caregivers reported current relationship closeness using the Whitlatch Relationship Closeness Scale. Linear mixed models examined associations between CG-CR closeness and NPI-12 total score or selected symptom domains over time (observation period: 2002-2012). RESULTS: In unadjusted linear mixed models, higher closeness scores were associated with a five-point lower NPI-12 score and a one-point lesser increase in NPI-12 per year. NPI scores also showed lower affective cluster scores (two points) and lesser increase in psychosis cluster (approximately 0.5 points per year) and agitation/aggression (0.16 points per year) for each unit increase in closeness. When controlling for NPI caregiver distress, associations between closeness and NPSs diminished to a 0.5-point lesser increase in total NPI-12 score per year. Adjusted models for NPI domains/clusters showed -0.32 points per year for the psychosis cluster, -0.11 points per year for agitation/aggression, and -0.67 overall for the affective cluster. CONCLUSION: Higher CG-CR closeness, a potentially modifiable factor, is associated with lower NPS severity and may provide a target for intervention.