Effect of necessity-concern framework and polypharmacy on treatment adherence in psychiatric patients. Comparing an Argentinian with a Spanish sample.

The Argentinian sample replicated the previous finding that patient beliefs regarding necessity and concern were associated with poor adherence to prescribed medications. Polypharmacy had an additive role decreasing adherence in both samples. In both samples, when prescribed ≥4 psychiatric medications, patients reported adherence to only two-third of the medications.