DMD and depressive symptom measurement: Those associated with an increased likelihood of persisting on DMD therapy include female gender, age of 18 to 34, having an HMO insurance plan type, higher degrees of comorbidity (Deyo-Charlson Comorbidity Index), pre-index comorbidities of depression, headache, or urinary tract infection, and pre-index use of antidepressants or muscle relaxants.