A large-scale validation study of the Medication Adherence Rating Scale (MARS).
Adherence to medication is an important predictor of illness course and outcome in psychosis. The Medication Adherence Rating Scale (MARS) is a ten-item self-report measure of medication adherence in psychosis [Thompson, K., Kulkarni, J., Sergejew, A.A., 2000. Reliability and validity of a new Medication Adherence Rating Scale (MARS) for the psychoses. Schizophrenia Research. 42. 241-247]. Although initial results suggested that the scale has good reliability and validity, the development sample was small. The current study aimed to establish the psychometric properties of the MARS in a sample over four times larger. The scale was administered to 277 individuals with psychosis, along with measures of insight and psychopathology. Medication adherence was independently rated by each individual's keyworker. Results showed the internal consistency of the MARS to be lower than in the original sample, though adequate. MARS total score correlated weakly with keyworker-rated adherence, hence concurrent validity of the scale appeared only moderate to weak. The three factor structure of the MARS was replicated. Examination of the factor scores suggested that the factor 1 total score, which corresponds to the Medication Adherence Questionnaire [Morisky,D.E., Green,L.W. and Levine,D.M., 1986. Concurrent and predictive validity of a self-reported measure of medication adherence. Medical Care. 24, 67-74] may be a preferable measure of medication adherence behaviour to the total scale score.
Fialko
Laura
L
Department of Psychology, Institute of Psychiatry, King's College London, University of London, UK. l.fialko@iop.kcl.ac.uk
Garety
Philippa A
PA
Kuipers
Elizabeth
E
Dunn
Graham
G
Bebbington
Paul E
PE
Fowler
David
D
Freeman
Daniel
D
D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001294:Attitude to Health; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D010349:Patient Compliance / Q000523:psychology* / Q000706:statistics & numerical data; D010555:Personality Inventory / Q000706:statistics & numerical data*; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011594:Psychometrics; D011618:Psychotic Disorders / Q000188:drug therapy* / Q000523:psychology; D012008:Recurrence; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000188:drug therapy*; D012563:Schizophrenia, Paranoid / Q000188:drug therapy / Q000523:psychology; D012565:Schizophrenic Psychology; D011795:Surveys and Questionnaires
D014150:Antipsychotic Agents