Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Treatment-resistant and recurrent depression
Psychiatry · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
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Deterioration during apparent resistance
Escalating suicide intent, psychotic depression, catatonia, severe malnutrition, dehydration or inability to maintain basic safety requires urgent specialist and physical care rather than another routine sequential prescription.
Action: Provide immediate medical and environmental safety, arrange same-day specialist assessment and consider admission, combined treatment or ECT according to need and preference. Review capacity, dependants and medication access and use the least restrictive lawful framework.
Purpose and principles
Verify whether treatment has truly been adequate, revisit diagnosis and barriers, use shared stepwise switching or augmentation with specialist monitoring, and build relapse prevention from residual symptoms, recurrence history and the person's priorities.
Treatment resistance is a prompt to investigate, not a fixed identity. Reconstruct the current episode and every intervention. For medicines, record indication, preparation, dose, duration at therapeutic dose, missed doses, interactions, benefit, adverse effects and withdrawal. For therapy, record modality, formulation, number and frequency of sessions, practitioner competence, engagement, homework or behavioural exposure and access barriers. Determine whether improvement was absent, partial or lost after an initial response and whether function changed differently from symptom scores.
Reopen diagnosis and mechanism. Ask again about hypomania, mania, mixed activation, psychosis, trauma, anxiety, obsessive symptoms, eating disorder, ADHD or autism, substance use and personality-related needs. Review thyroid and other physical causes, pain, sleep apnoea, reproductive context and medicines. Examine housing, debt, domestic abuse, discrimination, isolation and inaccessible care. Non-adherence may reflect adverse effects, cost, shame, executive difficulty or disagreement and should be understood rather than moralised.
Indications, selection and cautions
Pseudo-resistance
The apparent failure reflects incorrect diagnosis, inadequate dose or duration, missed treatment, inaccessible therapy, interaction, substance use or an untreated maintaining factor.
Partial response
Some symptoms or functions improve while clinically important residual features persist, informing optimisation or combination rather than assuming complete failure.
True complex non-response
Several adequately delivered evidence-based treatments fail despite diagnostic review, adherence and barrier correction, supporting specialist resistance care.
High relapse risk
Repeated or severe episodes, residual symptoms, recent recurrence, major consequences or rapid previous relapse favour structured maintenance and psychological prevention.
Augmentation toxicity risk
Renal, thyroid, cardiac, metabolic, neurological or interaction factors make lithium or antipsychotic augmentation unsafe without specialist monitoring.
Red flags requiring action
The label treatment resistant should not be applied before confirming diagnosis, bipolarity, adequate dose and duration, adherence, therapy delivery, substances, physical illness and social barriers.
Repeated antidepressant activation, mixed features or episodic reduced sleep need suggests bipolarity and makes further antidepressant escalation potentially harmful.
Assessment before treatment
01Treatment adequacy inventoryFirst step
Why
Verify medication dose, duration, adherence and harm and psychological modality, delivery, attendance and formulation fit.
Interpretation and limitations
A referral, subtherapeutic exposure or intolerable early stop is not equivalent to an adequate failed trial; document limitations before labelling resistance.
02Diagnostic and maintaining-factor review
Why
Reassess bipolarity, psychosis, comorbidity, substances, physical illness, sleep, pain and social adversity.
Interpretation and limitations
A newly identified mechanism may require a different treatment pathway rather than another antidepressant with the same assumptions.
03Augmentation baseline
Why
Assess weight, renal, thyroid, calcium, metabolic, cardiovascular, movement and interaction risks for the proposed strategy.
Interpretation and limitations
Select tests by medicine. Abnormalities may require correction, alternative treatment or closer specialist monitoring.
04Lithium serum monitoring
Why
Guide augmentation exposure and detect accumulation after initiation, dose change, illness or interacting medicine.
Interpretation and limitations
Use a 12-hour level and current NICE and local targets; toxicity can occur with dehydration or renal change even near a previous stable result.
Treatment approach
01Verify resistanceAudit diagnosis and treatment exposureFirst stepDepression has not improved sufficiently after one or more interventions.+
1Reconstruct symptoms, function and every medicine and therapy trial with dose, duration, adherence, delivery, benefit and harm.
2Reassess bipolarity, comorbidity, substances, physical causes and social or access barriers and correct remediable factors.
3Agree whether the previous trial was adequate and define the next treatment target and observable response marker.
02Escalate treatmentSwitch, combine or augment deliberatelyEscalationAn adequate intervention has failed or produced only insufficient response.+
1Discuss optimisation, switching, psychological change or combination, incorporating previous benefit, adverse effects and patient preference.
Regimens, contraindications and interactions
A NICE-recommended option when two antidepressants have produced no or inadequate response during the current major depressive episode.
Vortioxetine
Use 10 mg orally once daily in adults under 65, adjusting between 5 and 20 mg daily by response; start 5 mg once daily from age 65.
Review nausea, bleeding, hyponatraemia, mania and serotonergic interactions; MAOI combinations are contraindicated and switching requires current product-specific washout guidance.
An evidence-based augmentation option after inadequate antidepressant response when the person accepts serum and physical monitoring.
Lithium augmentation
Initiate and adjust under specialist-informed care to a 12-hour serum level usually at least 0.4 mmol/L and not above 1.0 mmol/L, using lower ranges when clinically appropriate.
Check renal, thyroid, calcium, weight, pregnancy and ECG indications; explain toxicity, hydration and interactions with NSAIDs, ACE inhibitors, ARBs and diuretics and use formulation-consistent prescribing.
Complications, monitoring and follow-up
Review symptom domains and concrete function after each optimisation, switch or augmentation at an agreed interval, including suicide and activation assessment.
For lithium, check a 12-hour level one week after initiation and dose change and weekly until stable, then at the guideline interval with more frequent testing for risk factors.
Monitor renal, thyroid, calcium, weight and adverse effects during lithium and metabolic, movement, prolactin, cardiovascular and ECG factors during antipsychotic augmentation.
Review maintenance treatment at least every six months for mood, function, adverse effects, adherence, relapse factors and the person's wish to continue.
Update early-warning and crisis plans after each relapse, identifying whether the intervention failed, was inaccessible or was started too late.
Special situations
Failure has a mechanism
No response can reflect diagnosis, pharmacology, delivery, access or maintaining adversity, and each mechanism points toward a different next step.
Partial benefit is evidence
Improvement in sleep or initiation can indicate useful mechanism even when mood remains low, supporting targeted optimisation or complementary therapy.
Augmentation adds burden
Potential benefit must be weighed against blood tests, metabolic effects, interactions, pregnancy implications and complexity that may reduce adherence.
Residual symptoms predict
Persistent insomnia, avoidance, hopelessness or cognitive difficulty after remission can precede relapse and are active prevention targets.
Maintenance is a decision
Long-term medication should be reviewed with current benefit, harm and preference rather than repeated indefinitely because it once worked.
Common pitfalls
01
Labelling resistance after a low dose, short duration or inaccessible therapy.
02
Adding another antidepressant without repeating bipolar and interaction assessment.
03
Combining medicines without specialist monitoring, a response target and stopping plan.
04
Using lithium without renal, thyroid, calcium, interaction and serum-level safeguards.
05
Treating adverse effects or non-adherence as patient failure instead of clinical information.
06
Stopping effective relapse-prevention treatment abruptly after remission.
07
Focusing on score remission while residual functional and suicide risks remain.
Practice
Two practice questions
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Question 1 of 2
0 correct
PsychiatryOriginal SBA
Before resistance label
A patient is called treatment resistant after stopping one SSRI at two weeks because of nausea and attending two CBT sessions. What should happen first?
Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources
Sources and review status
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.
Agree the next step from prior evidence and preference. NICE options include increasing dose within licensed limits when tolerated, switching antidepressant, combining medication with psychological therapy or changing psychological approach. Switching may require direct change, cross-taper, taper then washout or specialist supervision depending on pharmacology; MAOIs and fluoxetine create particular interaction timing concerns. Combining antidepressants, lithium or antipsychotic augmentation increases risk and generally warrants specialist input and a defined monitoring and stopping plan.
Vortioxetine is recommended by NICE technology appraisal as an option after no or inadequate response to two antidepressants in the current episode. Lithium augmentation is guided by serum concentration and clinical response and requires renal, thyroid, calcium, weight and interaction assessment. Antipsychotic augmentation may cause metabolic, cardiovascular, movement and prolactin harms. ECT is an option for selected severe depression requiring rapid response, after other treatments fail or when previous effective experience and current informed preference support it.
Recurrent depression needs relapse prevention. Identify residual symptoms, number and severity of episodes, recent recurrence, consequences, ongoing stress and prior rapid relapse after stopping. Continue the antidepressant dose that achieved remission unless there is a reason to reduce, and consider relapse-prevention CBT or mindfulness-based cognitive therapy according to preference and availability. Review at least periodically for mood, function, adherence, adverse effects, physical monitoring and desire to continue, avoiding indefinite automatic repeats.
Key points
Define the current episode, residual symptoms and function and list every psychological and medication trial with dose, duration, adherence, benefit, harm and reason for stopping.
Reassess bipolar disorder, psychosis, trauma, substance use, neurodevelopment, personality-related needs, pain, sleep, endocrine disease and social adversity before escalation.
Confirm that psychological treatment was accessible, formulation matched, adequately delivered and attended; referral or a few sessions is not an adequate trial.
For medication non-response, discuss dose optimisation within licensed limits, switching within or between classes, adding psychotherapy or specialist combination and augmentation options.
Vortioxetine is a NICE option for adults whose current major depressive episode has responded inadequately to two antidepressants.
Lithium augmentation is level guided and requires weight, renal, thyroid and calcium baseline, interaction review, regular 12-hour serum levels and toxicity education.
Antipsychotic augmentation requires informed off-label or indication discussion, metabolic and movement baseline, and review of cardiac, prolactin and sedation risk.
ECT is considered for severe depression when rapid response is needed, other treatments have failed or previous benefit and informed preference support it.
Psychotic features, catatonia, severe functional collapse or persistent suicide danger require specialist treatment intensity irrespective of the number of previous trials.
Lithium and antipsychotic augmentation require physical baseline, interaction review and ongoing serum, renal, thyroid, calcium, metabolic, movement or ECG monitoring as applicable.
Combining antidepressants increases adverse-effect and interaction burden and should follow specialist-informed discussion rather than being added casually in primary care.
Use the formulation to choose continuation, psychological prevention and review intensity rather than applying a fixed duration to everyone.
2
Use specialist input for antidepressant combinations, lithium, antipsychotic augmentation, MAOI strategies or ECT and complete required baseline assessment.
3Set dose or exposure, monitoring, response timeframe and stopping criteria and review suicide risk and function during the transition.
03Prevent recurrenceMaintain recovery with planned reviewThe person is in remission but has factors indicating substantial relapse risk.+
2Discuss continuation of effective medication and relapse-prevention CBT or mindfulness-based cognitive therapy, including burdens and withdrawal concerns.
3Schedule reviews of mood, function, harm and preference and maintain a personalised plan for early symptoms and rapid access.
For recurrent depression, continue effective treatment and offer relapse-prevention psychological care, with scheduled review of benefits, harms and the person's wish to continue.