Effects of chronic daily headache with subclinical depression on brain volume: A systematic review and meta‐analysis

Background and Objective The relationship between chronic daily headache (CDH), depression symptoms, and brain volume remains unclear. Methods To investigate the effects of CDH on brain volume and the impact of depressive symptoms (DSs) as well as the effects of demography and medication overuse, PubMed, Embase, and Web of Science databases were systematically searched using appropriate keyword strings to retrieve observational studies from inception to May 2023. Results Two distinct comparisons were made in CDH patients: (1) those with DSs versus their pain‐free counterparts and (2) those without DSs versus pain‐free controls. The first comprised nine studies enrolling 225 CDH patients with DSs and 234 controls. Beck depression inventory, Hamilton depression scale, and Hospital anxiety/depression scale were used to assess DSs, revealing significantly more DSs in CDH patients with DSs compared to their controls (all p