Current State of the Science: A number of researchers have investigated the relationship between mood and medication adherence, with mixed results (Dunbar-Jacob et. al., 1995). Personality and adherence have not been systematically studied; researchers in the area suggest further study with the five-factor model (e.g. Christensen & Smith, 1995; Wiebe & Christensen, 1996). The relationship between cognitive functioning and medication adherence has not been widely studied; it has long been assumed that the cognitive changes of normal aging contribute to noncompliance (Nikolaus et. al., 1996). Medication adherence and cognitive function are intuitively related but under-studied. Mood and personality are confounded with each other and with cognitive functioning. If cholesterol levels are significantly affected by pharmacological treatment, then the impact of cognitive deficits on adherence with treatment becomes important. Tailoring psycho-educational interventions to address those deficits would benefit clinical and research professionals and populations.
Objectives: This pilot study was a secondary analysis to examine the relationship between adherence with medication regimes for lowering serum cholesterol and several domains of psychological and cognitive functioning.
Design: Patients in the original study were randomly assigned to either drug or placebo treatment and to one of three intervention protocols, resulting in a 2 X 3 design.
Population, Sample, Setting, Years: One hundred seventy-two subjects participated in a randomized trial of the behavioral correlates of cholesterol lowering medication, over a 3-month period (1992-95) at the University of Pittsburgh Medical Center. Demographic data is missing on 11 subjects; of the 161 participants with data, there were 86 men and 75 women, mean age was 46.4 SD=8.8. Fifteen subjects were African American, 143 were Caucasian, 3 were Hispanic or Asian. Mean education level was 15.3 SD=3.1.
Variables Studies Together: Medication adherence electronically measured, personality using the NEO, STAI, Beck depression inventory, and memory.
Methods: Subjects underwent neuropsychological testing and completed a battery of self-report psychological measures at baseline. Medication adherence was measured with MEMS electronic cap monitoring. The group mean for adherence was below the generally accepted 80% level throughout the period and declined over time (from 72.8% at 1 week to 67.6% at 24 weeks.
Findings: There were a number of significant relationships between psychological and neuropsychological factors. Conscientiousness, according to the five-factor model of personality (Costa & McCrae, 1992) was positively correlated with over-all adherence; trait anxiety and depression were negatively correlated with over-all adherence. Estimated IQ and visuo-spatial/constructional ability were positively correlated with over-all adherence over the 3-month period.
Conclusions/Implications: This study is the largest and most comprehensive investigation of personality, emotional status, cognitive functioning and adherence among non-psychiatric patients. Findings not only support broader, more intensive psychological and cognitive assessments in adherence research to better explain predictors of adherence, but suggest that interventions to improve adherence will be more effective when the underlying dynamics are addressed.
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