The Nursing Assessment of Medication Acceptance: the reliability and validity of a schizophrenia medication adherence scale.

Background: Many patients with schizophrenia have low medication adherence. There is, however, no objective assessment scale that can be used by nurses or caregiver specialists. The Nursing Assessment of Medication Acceptance (NAMA) was developed to assess patients' medication adherence. The aim of this study was to examine the validity and reliability of the NAMA in patients with schizophrenia.

Methods: A total of 121 Japanese patients with schizophrenia were enrolled. All patients underwent evaluation using the NAMA and the Drug Attitude Inventory (DAI-10). Reliability was investigated using a test-retest method and a parallel-test method. To determine the test-retest reliability of the NAMA, we tested 101 schizophrenia patients twice, with the second assessment 2-4 weeks after the date of the first assessment. For validity verification, standard-related validity and the degree of concordance with the DAI-10 scores were measured.

Results: The Cronbach's alpha value of the NAMA in schizophrenia was 0.88. The test-retest correlation coefficients were all between 0.53-0.74. The total scores and all subscores for the NAMA were significantly correlated, and the NAMA total scores were significantly correlated with the DAI-10 total scores.

Conclusions: The NAMA shows good reliability and validity in measuring medication adherence in schizophrenia.