PassFinals
Mental Health

Depression

A clinically diagnosed disorder of mood, interest, cognition, energy and function in which severity, suicide risk, bipolar history and patient preference determine the treatment pathway.

In a nutshell

Diagnose depression clinically, establish severity and function, screen for bipolarity and psychosis, and assess suicide or self-harm risk at every meaningful review. Use lower-intensity options first for less severe depression; agree psychological, antidepressant or combination treatment for more severe depression; review early, escalate risk or non-response, continue after remission and taper gradually.

Classic presentation

At least 2 weeks of persistent low mood or anhedonia with reduced energy, sleep or appetite change, poor concentration, guilt or hopelessness and functional impairment, without a better bipolar, psychotic, substance-related or physical explanation.

Key points

  • Severity is less severe versus more severe in the current NICE framework; PHQ-9 supports assessment and outcome monitoring but does not replace clinical judgement.
  • Ask about mania or hypomania before prescribing: bipolar depression needs the bipolar pathway, and antidepressant monotherapy can precipitate or worsen mania.
  • Ask directly about suicide and self-harm, intent, plans, means, previous acts, protective factors and support. Do not use a risk score to predict suicide or decide discharge.
  • Less severe depression: offer guided self-help, psychological or behavioural treatment and exercise options; do not routinely offer an antidepressant first line unless preferred or clinically indicated.
  • More severe depression: shared first-line options include an antidepressant plus individual CBT, individual CBT, an antidepressant or another NICE-recommended high-intensity psychological treatment.
  • Review between 2 and 4 weeks after starting treatment, or after 1 week for ages 18 to 25 or particular suicide concern; monitor response, side effects, activation and suicidal thoughts.
  • Continue an effective antidepressant for at least 6 months after remission, consider longer prevention when relapse risk is high, and taper gradually rather than stopping abruptly.

First-line investigation

Clinical symptom and functional assessment with collateral where useful, individualised suicide/self-harm formulation, bipolar and psychosis screen, and targeted physical tests when indicated.

Management

Establish safety and the correct diagnosis

  • Assess suicidal thoughts, intent, plans, means, previous self-harm, psychosis, mania, substance use, self-neglect and support; escalate urgently if the person cannot stay safe.1,4
  • Screen for bipolarity, psychosis, substance effects and physical causes before committing to a unipolar depression pathway.1,3

Grade severity and choose the first treatment

  • Use clinical judgement, function and a validated outcome measure to classify less severe versus more severe depression; make a shared decision about treatment and goals.1,2
  • Offer lower-intensity psychological, behavioural or exercise options for less severe depression; for more severe depression discuss individual CBT, antidepressant treatment or combination treatment.1,2

Prescribe and monitor safely

  • When medication is chosen, use an SSRI as the usual class choice for most adults and check current BNF/local formulary details for the individual drug, dose, interactions and physical-health precautions.1,7
  • Review at 1 week for ages 18 to 25 or particular suicide concern, otherwise between 2 and 4 weeks; monitor response, adherence, side effects, activation and suicidal ideation.1,5

Escalate crisis, psychosis, bipolarity or non-response

  • Use crisis resolution/home treatment or inpatient care when more severe depression cannot be safely supported in the community, particularly with suicide, self-harm, harm-to-others or self-neglect risk.1,4
  • Refer psychotic or life-threatening depression urgently; specialist options include antidepressant plus antipsychotic treatment and ECT when a rapid response is needed or other treatments have failed.1

Prevent relapse and taper safely

  • Continue effective antidepressant treatment for at least 6 months after remission and agree relapse warning signs, support, crisis contacts and review points.1,2
  • Taper gradually over a person-led timeframe, monitor withdrawal and returning symptoms, and communicate the plan to the clinicians who will provide follow-up.1,7

Exam traps

  • A past period of mania or hypomania changes the diagnosis to bipolar disorder; do not prescribe unopposed antidepressant treatment as if it were unipolar depression.
  • A PHQ-9 score supports severity and monitoring but cannot replace the clinical formulation or a direct suicide assessment.
  • Do not routinely use antidepressants first line for a new episode of less severe depression unless the person prefers them or there is another NICE-supported reason.
  • Review at 1 week for ages 18 to 25 or particular suicide concern, not a blanket under-30 rule; otherwise review within 2 to 4 weeks and monitor suicidal ideation.
  • Psychotic depression, severe self-neglect, inability to eat or drink and immediate suicide risk need specialist or crisis escalation; routine primary-care follow-up is not enough.
  • Stopping an SSRI suddenly can cause withdrawal and relapse; taper in stages and monitor both.
  • Tricyclic overdose toxicity and drug interactions matter when suicide risk is high; limit quantities and choose the safest appropriate option.

Illustrations

Depression assessment and safety formulationA clinical assessment map linking symptoms and functional impairment with severity, bipolar and psychosis screening, physical causes, suicide and self-harm assessment, protective factors and treatment preference.PassFinals · original
Stepped treatment pathwayA two-branch pathway showing lower-intensity options for less severe depression and shared first-line psychological, antidepressant or combination options for more severe depression, with escalation for risk, psychosis or non-response.PassFinals · original
Antidepressant review and withdrawal timelineTimeline showing early safety review, 2-to-4-week treatment review, continuation after remission and gradual tapering with monitoring for withdrawal and relapse.PassFinals · original

Key sources

  1. NICE NG222, Depression in adults: treatment and management, recommendations (NG222)
  2. NICE NG222, information for the public (NG222 public information)
  3. NICE CG185, Bipolar disorder: assessment and management, recommendations (CG185)Updated 2 Sept 2025
  4. NICE NG225, Self-harm: assessment, management and preventing recurrence, recommendations (NG225)
  5. MHRA, Selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs): use and safety (MHRA SSRI/SNRI safety)
  6. NHS, sudden confusion (delirium) (NHS sudden confusion)
  7. BNF, sertraline (BNF sertraline)
  8. NICE NG222, update information (NG222 update)

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.