Treatment duration with selective serotonin reuptake inhibitors among children and adolescents in Finland: a nationwide register study

Purpose We assessed treatment duration with selective serotonin reuptake inhibitors (SSRIs) among children and adolescents and investigated the association between treatment duration, age, sex, active ingredient, season of initiation, and reimbursement rate. Method Data on reimbursed SSRIs dispensed to children and adolescents aged <18 years in noninstitutional settings in Finland from 1999 to 2005 were extracted from the National Prescription Register. The association between treatment duration and explanatory factors was analyzed using Cox proportional hazards models. Results SSRIs were reimbursed for 3,710 (35.8%) male and 6,666 female (64.2%) patients from 1999 to 2004, of whom 3,853 (37.1%) received <= 100 days' supply. Age <= 11 years [adjusted hazard ratio (HR) 0.87; 95% confidence interval (CI), 0.80-0.94] and 12-15 years (HR 0.89; 95% CI 0.84-0.93) was associated with longer treatment duration compared with adolescents aged 16-17 years. Shorter treatment duration was associated with initiating treatment from September to November compared with the other seasons. Recipients of a higher reimbursement rate had longer treatment duration (HR 0.46, 95% CI 0.39-0.55) compared with those who received a lower reimbursement rate. Shorter treatment duration was weakly associated with use of fluvoxamine (HR 1.16; 95% CI 1.03-1.30) compared with fluoxetine. Conclusions Shorter treatment duration was less common among younger children, when initiated from September to November and among recipients of a higher reimbursement rate.