The necessity-concern framework in the assessment of treatment adherence of psychiatric patients and the role of polypharmacy in a Spanish sample.

OBJECTIVE

This study compares three measures (necessity and concern scores, the necessity-concern differential, and a skeptical attitude vs. three other attitudes) for studying the relationship between the necessity-concern framework and treatment adherence after considering the number of prescribed drugs.

METHODS

The sample included 588 consecutive adult psychiatric outpatients in the Canary Islands, Spain. The necessity-concern framework was assessed using a specific subscale of the Beliefs about Medicines Questionnaire. Adherence (yes/no) to 1,101 prescribed psychiatric drugs was assessed using the Sidorkiewicz adherence tool.

RESULTS

In the three logistic regression models including 1,101 drugs, with adherence as the dependent variable, the highly significant odds ratios (ORs) and their 95% confidence intervals (CIs) were (a) OR = 1.57 (CI = 1.37-1.79) for necessity and OR = 0.747 (CI = 0.660-0.847) for concern; (b) OR = 1.44 (CI = 1.32-1.58) for the necessity-concern differential; and (c) OR = 0.452 (CI = 0.343-0.597) for a skeptical attitude (yes/no), defined as low necessity and high concern. In patients taking five or six drugs, adherence was associated with extremely high/low ORs for necessity, concern, and the differential.

CONCLUSION

If replicated, our results suggest clinicians need to pay careful attention to each drug in each patient taking five or six drugs, emphasize necessity, and listen carefully to patient concerns.