Attitudes toward medications and the relationship to outcomes in patients with schizophrenia

The determinants of attitudes toward medication (ATM) are not well elucidated. In particular, literature remains equivocal regarding the influence of cognition, adverse events, and psychiatric symptomatology. This study evaluated relationships between those outcomes in schizophrenia and ATM. This is a retrospective analysis of data collected during the Texas Medication Algorithm Project (TMAP, n=307 with schizophrenia-related diagnoses), in outpatient clinics at baseline and every 3 months for =1 year (for cognition: 3rd and 9th month only). The Drug Attitude Inventory (DAI-30) measured ATM, and independent variables were: cognition (Trail Making Test [TMT], Verbal Fluency Test, Hopkins Verbal Learning Test), adverse events (Systematic Assessment for Treatment-Emergent Adverse Events, Barnes Akathisia Rating Scale), psychiatric symptomatology (Brief Psychiatric Rating Scale, Scale for Assessment of Negative Symptoms [SANS]), and medication adherence (Medication Compliance Scale). Analyses included binary logistic regression (cognition, psychiatric symptoms) and chi-square (adverse events, adherence) for baseline comparisons, and linear regression (cognition) or ANOVA (adverse events, adherence) for changes over time. Mean DAI-30 scores did not change over 12 months. Odds of positive ATM increased with higher TMT Part B scores (p=0.03) and lower SANS scores (p=0.02). Worsening of general psychopathology (p<0.001), positive symptoms (p<0.001), and negative symptoms (p=0.007) correlated with negative changes in DAI-30 scores. Relationships between cognition, negative symptoms, and ATM warrant further investigation. Studies evaluating therapies for cognitive deficits and negative symptoms should consider including ATM measures as endpoints. Patterns and inconsistencies in findings across studies raise questions about whether some factors thought to influence ATM have nonlinear relationships.