Stepped care by severity (PHQ-9)
By PHQ-9 band.
1Mild (5–9): watchful waiting, lifestyle measures (sleep, exercise, alcohol), self-help/online CBT; review in 2–4 weeks.
2Moderate (10–14): Mental Health Treatment Plan + psychological therapy (CBT); consider an antidepressant if preferred or prior good response.
3Moderately severe (15–19): psychological therapy + antidepressant together; review at 2 and 4 weeks.
4Severe (20–27): antidepressant + psychological therapy; consider psychiatry input; urgent pathway if safety risk.
5Treatment-resistant / crisis: refer psychiatry; consider augmentation or ECT pathway.
Choosing the antidepressant. First-line agent depends on patient profile (pregnancy, cardiac disease, age, comorbid pain, prior response) — see MH-05B for the choice, switching and stopping detail.
Initiation — what to tell the patient
Mood effects usually take 2–4 weeks to start, up to 6–8 weeks for full response. Early nausea/headache/insomnia commonly settle within 1–2 weeks. Sexual side-effects are common and often dose-related — ask directly, patients rarely volunteer this. In adolescents and young adults, suicidal thinking can transiently increase in the first 1–4 weeks — flag this and arrange early review.
Monitoring schedule
- Week 1–2: brief check (phone or short consult) — tolerability and safety/suicide-risk check, especially <25yo.
- Week 4: full review with repeat PHQ-9 — optimise dose if partial response.
- Week 8–12: repeat PHQ-9 — consider switching if no response despite an adequate trial (see MH-05B).
- Ongoing: 3-monthly while stable; continue 6–12 months after remission of a first episode, longer if recurrent.
Mental health care planning. An MBS Mental Health Treatment Plan (e.g. item 2715) supports Better Access psychology sessions, but eligibility rules changed from Nov 2025 (MyMedicare practice/usual-GP linkage) — see MH-08 for the full pathway and confirm the current item number at mbsonline.gov.au.