“…On the basis of previous research showing their associations with mental health service costs (Durbin et al , 2015; Twomey et al , 2015a), initial adjustments were made for age, sex, marital status, ethnicity, employment status, area-level deprivation, general health comorbidity, psychiatric comorbidity, clinician-rated severity of illness, NHS costs incurred in the 3 months before baseline, functioning, depressive symptom severity and anxiety symptom severity. To safeguard statistical power, we subsequently removed several covariates that (a) were not associated with costs in exploratory analysis and (b) yielded P values more than 0.20 in this association.…”