Table 1.

Overview of the central health registries and diagnostic codes used

Register	Codes	Interpretation/wording
Norwegian Control and Payment of Health Reimbursements Database (CPHR – the primary care database)
ICPC-2	P73, P76	Affective disorder, Depressive disorder
ICD-10	F32-F34	Depressive episode, recurrent depressive disorder, persistent mood (affective) disorder
Norwegian Prescription Database (NorPD)
Drug ATC-codes	N06A*	Antidepressants
Reimbursement codes ICD-10	F32-F34, -F3	Affective disorders needing treatment, Affective disorders
Reimbursement codes ICPC-2	P73, P76, -73
Diagnosis recorded in Norwegian Patient Registry (NPR – the specialist care registry)
ICD-10	F32-F34	Depressive episode, recurrent depressive disorder, persistent mood (affective) disorder

* any digit after this, indicating all antidepressants