Large posttraumatic stress disorder improvement and antidepressant medication adherence.

Background: Patients with vs. without posttraumatic stress disorder (PTSD) are more likely to have poor antidepressant medication (ADM) adherence but it is unclear if improved PTSD is associated with ADM adherence. We determined if clinically meaningful PTSD symptom reduction was associated with ADM adherence.

Methods: Electronic health record data (2008-2015) was obtained from 742 Veterans Health Affairs (VHA) patients using PTSD specialty clinics with a PTSD diagnosis and PTSD checklist (PCL) score ≥50. The last PCL in the exposure year after the first PCL≥50 was used to identify patients with a clinically meaningful PCL decrease (≥20 point) versus those without (< 20 point). Patients had a depression diagnosis in the 12-months before the exposure year and received an ADM in the exposure year. Proportion of days covered ≥80% in exposure year defined adherence. Confounding was controlled using propensity scores and inverse probability of treatment weighting.

Results: Patients were 42.2 ± 13.1 years of age, 63.9% white and 18.9% had a clinically meaningful PCL decrease. After controlling for confounding variables, patients with vs. without a clinically meaningful PCL decrease were significantly more likely to be adherent (OR = 1.78; 95% CI:1.16-2.73). However, adherence remained low in both patients with and without meaningful PCL decrease (53.5% vs. 39.3%).

Limitations: The sample was limited to VHA patients. Patients may not have taken medication as prescribed.

Conclusions: Large reductions in PTSD symptoms are associated with ADM adherence. Prior literature suggests ADM adherence improves depression symptoms. Thus, PTSD symptom reduction may lead to better depression outcomes.