0

Has not had a single adequate trial of medication

1

Nonresponse to an adequate trial of one medication (monotherapy)

2

Failure to respond to two different adequate monotherapy trials of medications

with different pharmacological profiles (e.g., a TCA and SRI)

3

Stage 2 plus failure to response to one augmentation strategy

(e.g., Li or thyroid augmentation) of one of the monotherapies

4

Stage 3 plus a failure on a second augmentation strategy

5

Stage 4 plus failure to respond to ECT