Clinical Guideline Briefing
CANMAT
Major Depressive Disorder Management
2024
Published May 18, 2026
10 min read
CANMAT launches 2024 guideline for Major Depressive Disorder Management
The updated CANMAT guideline extends recommended antidepressant maintenance duration and emphasizes earlier adjunctive strategies for limited treatment response.
Headline change
Antidepressant maintenance treatment is now recommended for a minimum of 6 to 12 months after remission, an extension from the prior 6 to 9 months.
Bedside action
Review your MDD patients on antidepressants to ensure their maintenance duration aligns with the updated 6-12 month recommendation post-remission, especially those with recurrence risk factors.
The Canadian Network for Mood and Anxiety Treatments (CANMAT) has released its 2023 update to the clinical guidelines for Major Depressive Disorder (MDD) in adults. This comprehensive revision, building on the 2016 edition, integrates new evidence across psychological, pharmacological, lifestyle, and neuromodulation treatments, emphasizing personalized care and shared decision-making. Clinicians will find updated recommendations for treatment selection, monitoring, and strategies for inadequate response, with notable shifts in antidepressant maintenance and adjunctive therapy timing.
Versus the Previous Version
The 2024 CANMAT guidelines represent a significant update from the 2016 version, incorporating new evidence and refining recommendations across the spectrum of MDD management. Key changes reflect evolving understanding of treatment duration, the role of adjunctive therapies, and the integration of digital health interventions.
Antidepressant Maintenance
Previous version
The 2016 guidelines recommended that patients maintain treatment with antidepressants for 6 to 9 months after achieving symptomatic remission.
This version
The 2024 guidelines recommend all patients treated with antidepressants continue medication for a minimum of 6 to 12 months after achieving symptomatic remission.
Clinical impact Extend antidepressant maintenance for patients who have achieved remission from 6-9 months to 6-12 months, and longer for those with recurrence risk factors.
Adjunctive Strategies Timing
Previous version
The 2016 guidelines suggested considering adjunctive strategies after failure of one or more antidepressants, often in the context of treatment-resistant depression.
This version
The 2024 guidelines recommend that adjunctive strategies be considered earlier in the treatment algorithm, after limited response to the first or second antidepressant trial.
Clinical impact For patients with limited response to initial antidepressant trials, consider adding an adjunctive agent (e.g., atypical antipsychotic) sooner rather than switching multiple times.
Psychological Treatments
Previous version
The 2016 guidelines listed CBT, IPT, and BA as first-line psychological treatments, with CBASP, MBCT, PST, and STPP as second-line.
This version
The 2024 guidelines continue to recommend CBT, IPT, and BA as first-line. Transdiagnostic psychological treatment of emotional disorders and Metacognitive therapy (MCT) are new additions as second- and third-line, respectively.
Clinical impact Expand your understanding of psychological treatment options to include transdiagnostic approaches and MCT, especially for patients with comorbid anxiety or specific cognitive patterns.
Digital Health Interventions
Previous version
The 2016 guidelines did not include specific recommendations for Digital Health Interventions (DHIs).
This version
The 2024 guidelines introduce guided internet CBT (iCBT) DHIs as first-line monotherapy for mild depression and first-line adjunctive for moderate MDD.
Clinical impact Integrate guided iCBT DHIs into treatment plans for mild depression or as an adjunct for moderate MDD, considering accessibility and patient preference.
St. John's Wort
Previous version
The 2016 guidelines cited evidence for St. John's wort efficacy in mild depression.
This version
The 2024 guidelines recommend St. John's wort as a first-line treatment for mild MDE and a second-line for moderate MDE, with caution for drug interactions.
Clinical impact Consider St. John's wort as a first-line option for mild MDD, but remain vigilant for potential drug interactions, especially with serotonergic medications.
S-adenosyl-L-methionine (SAM-e)
Previous version
SAM-e was previously recommended as a second-line adjunctive treatment for mild to moderate MDE.
This version
SAM-e is now downgraded to a third-line treatment due to mixed findings in recent RCTs.
Clinical impact Re-evaluate the use of SAM-e; it is now a third-line option, suggesting less robust evidence for its efficacy compared to other treatments.
Omega-3 Fatty Acids
Previous version
Omega-3 fatty acids were recommended as a second-line intervention for mild-severity episodes.
This version
Omega-3 fatty acids are now downgraded to a third-line treatment due to insufficient high-quality evidence.
Clinical impact Adjust expectations for omega-3 fatty acids; they are now a third-line option with less clear evidence of benefit.
Ketamine/Esketamine
Previous version
The 2016 guidelines considered ketamine an experimental treatment, limiting its use to academic centers.
This version
The 2024 guidelines recommend intranasal esketamine and IV racemic ketamine as second-line adjunctive treatments for DTD, acknowledging their rapid antidepressant effects.
Clinical impact Consider intranasal esketamine or IV racemic ketamine as second-line adjunctive options for patients with difficult-to-treat depression, noting their rapid action and specific monitoring requirements.
Practice Notes
Consider these practical implications for your daily practice based on the updated guidelines:
Monitoring
Implement measurement-based care (MBC) routinely for all MDD patients.
MBC, using validated rating scales like PHQ-9, improves treatment adherence and outcomes. It helps identify non-responders and guides clinical decisions, enhancing patient engagement.
Caution
Be aware of increased suicide risk during antidepressant initiation and discontinuation.
The initial few weeks after starting any treatment and the month after stopping an antidepressant are higher-risk periods. Monitor patients closely, especially young adults, and ensure a safety plan is in place.
Implementation
Consider adjunctive strategies earlier for patients with limited response to initial antidepressants.
Instead of multiple antidepressant switches, adding an adjunctive agent (e.g., atypical antipsychotic) after the first or second trial may lead to faster response and remission, balancing efficacy with side effect burden.
Shared decision point
Prioritize patient preferences and shared decision-making in treatment selection.
Given the many evidence-based options, involve patients in choosing treatments, explaining risks, benefits, and local accessibility to align care with their values and needs.
Special population
Tailor antidepressant selection for older and younger adult patients.
For patients over 65, SSRIs may be less effective, while SNRIs like duloxetine may be more so. For those under 25, fluoxetine or agomelatine might be favored due to efficacy, adverse reactions, and discontinuation symptoms.
Do not miss
Consider ECT as a first-choice option in very severe or life-threatening MDD.
For severe MDE with psychotic symptoms, severe suicidal ideation, or rapidly deteriorating physical condition, electroconvulsive therapy (ECT) provides rapid and effective intervention.
Key Recommendations
The CANMAT 2024 guidelines provide a comprehensive, evidence-informed framework for managing Major Depressive Disorder in adults. These key recommendations cover the full spectrum of care, from initial assessment and treatment selection to monitoring, maintenance, and strategies for inadequate response.
Key recommendations13 highlighted
01
In adults with MDD and risk factors, when resources for follow-up are available, screen for depression using a validated scale (e.g., PHQ-2 followed by PHQ-9).
EvidenceThis recommendation is based on Level 3 evidence, primarily from observational studies and expert consensus, highlighting the importance of early detection in at-risk populations when follow-up resources are in place. The PHQ-2/PHQ-9 sequence offers similar sensitivity and better specificity than PHQ-9 alone.
For practiceIntegrate PHQ-2/PHQ-9 screening into routine care for at-risk patients, ensuring a clear pathway for positive screens.
CaveatScreening is only beneficial if resources are available for subsequent diagnostic assessment and treatment.
02
In adults with mild MDE and low safety risk, initiate psychotherapy (e.g., CBT, IPT, BA) as the preferred initial treatment.
EvidencePsychotherapy, such as CBT, IPT, and BA, is supported by Level 1 evidence as first-line psychological treatments. For mild MDE, it is preferred due to fewer risks compared to pharmacotherapy, if readily accessible.
For practiceOffer readily accessible psychotherapy as the first-line option for mild depression, discussing its benefits and lower risk profile.
CaveatAccessibility of psychotherapy can be a limiting factor.
03
In adults with severe MDE and psychotic symptoms, combine an antidepressant with an atypical antipsychotic medication.
EvidenceA Cochrane meta-analysis (12 studies, N=929) found antidepressant-antipsychotic combination more effective than monotherapy. This is supported by Level 1 evidence.
For practiceFor severe MDD with psychotic features, initiate combination therapy with an antidepressant and an atypical antipsychotic promptly.
CaveatStructured psychotherapy should be deferred until psychotic symptoms subside.
04
In adults with very severe MDE and/or life-threatening situations (e.g., severe suicide risk, physical deterioration), consider electroconvulsive therapy (ECT) as the first-choice option.
EvidenceECT has demonstrated high efficacy (65-75% response rates) for severe MDE, especially with psychotic or catatonic features, severe suicidal ideation, or deteriorating physical condition. It is supported by Level 1 evidence.
For practiceDo not delay considering ECT for critically ill MDD patients, especially with high suicide risk or severe physical decline.
CaveatECT requires general anesthesia and carries potential cognitive adverse effects, though modern techniques mitigate these.
05
In adults with mild or moderate MDE, recommend supervised exercise (low to moderate intensity, 30-40 min, 3-4 times/week for at least 9 weeks).
Line / StrengthFirst line
Level of EvidenceLevel 1
EvidenceMeta-analyses continue to support supervised exercise as a first-line monotherapy for mild depression and a second-line adjunctive treatment for moderate severity illness, with Level 1 evidence.
For practiceIntegrate supervised exercise as a first-line non-pharmacological option for mild MDD, and as an adjunctive treatment for moderate cases.
CaveatAdherence to exercise regimens can be a challenge for patients with MDD.
06
In adults with mild or moderate MDE, consider St. John's wort as a first-line treatment for mild MDE and second-line for moderate MDE.
Line / StrengthFirst line
Level of EvidenceLevel 1
EvidenceSt. John's wort has Level 1 evidence for efficacy in mild depression. It is recommended as first-line for mild MDE and second-line for moderate MDE.
For practiceOffer St. John's wort as a first-line option for mild MDD, but thoroughly review potential drug interactions due to its over-the-counter availability.
CaveatCaution for drug interactions, especially with serotonergic medications and potent CYP3A4 inducers.
07
In adults with mild or moderate MDE, recommend guided internet CBT (iCBT) DHIs as first-line monotherapy for mild depression and first-line adjunctive for moderate MDD.
Line / StrengthFirst line
Level of EvidenceLevel 1
EvidenceAn umbrella review of iCBT described medium to large effect sizes in 4 meta-analyses, supporting its efficacy. Guided iCBT is supported by Level 1 evidence.
For practiceUtilize guided iCBT DHIs as a primary treatment for mild depression or as a valuable adjunct for moderate cases, addressing potential access barriers.
CaveatChallenges with digital literacy, technology costs, and user engagement can be barriers.
08
In adults with MDD, use validated rating scales for measurement-based care (MBC) to guide clinical decisions and monitor treatment outcomes.
EvidenceHigh-quality trials and systematic reviews show MBC improves medication adherence and outcomes in MDD. MBC is supported by Level 1 evidence.
For practiceIntegrate validated rating scales (e.g., PHQ-9) into every patient encounter to objectively track progress and inform treatment adjustments.
CaveatScales should complement, not replace, comprehensive clinical interviews.
09
In adults with MDD who achieved symptomatic remission on antidepressants, continue antidepressant medication for a minimum of 6 to 12 months after achieving symptomatic remission.
Line / StrengthFirst line
Level of EvidenceLevel 1
EvidenceNew meta-regression evidence suggests extending maintenance treatment for 6 to 12 months after remission adds benefit compared to stopping before 6 months. This is supported by Level 1 evidence.
For practiceExtend antidepressant maintenance to 6-12 months post-remission for all patients, and consider longer durations for those with recurrence risk factors.
CaveatPatients with risk factors for recurrence may require treatment for 2 years or more.
10
In adults discontinuing antidepressants, taper antidepressants gradually over several weeks or months, extending time between dose reductions towards the end of the taper.
Line / StrengthFirst line
Level of EvidenceLevel 4
EvidenceThis pragmatic approach is recommended to mitigate discontinuation symptoms, which can affect up to 50% of patients. While evidence for specific tapering schedules is low quality, gradual tapering is expert consensus (Level 4).
For practiceAlways plan a slow, gradual taper for antidepressants, educating patients about potential discontinuation symptoms and adjusting the schedule as needed.
CaveatRapid discontinuation may be necessary for severe side effects; fluoxetine may not require tapering due to its long half-life.
11
In adults with MDD with limited response to initial antidepressant trials, consider adjunctive strategies, particularly with atypical antipsychotics (e.g., aripiprazole, brexpiprazole), earlier in the treatment algorithm.
EvidenceRCTs directly comparing switching to adjunctive strategies show superior outcomes for adjunctive agents, with greater evidence for efficacy and shorter time to response/remission. Supported by Level 1 evidence.
For practiceFor partial responders to initial antidepressants, consider adding an atypical antipsychotic like aripiprazole or brexpiprazole before switching to multiple other antidepressants.
CaveatAdjunctive agents may have a greater side effect burden than antidepressant monotherapy.
12
In adults with TRD, consider repetitive transcranial magnetic stimulation (rTMS) as a first-line neuromodulation treatment.
Line / StrengthFirst line
Level of EvidenceLevel 1
EvidencerTMS shows efficacy for DTD with response rates of 40-50%, with Level 1 evidence for protocols like high-frequency rTMS to left DLPFC or iTBS. It is less invasive than ECT and has no cognitive side effects.
For practiceOffer rTMS as a first-line neuromodulation option for patients with TRD, especially if medication tolerability is a concern or if they prefer a non-pharmacological approach.
CaveatAccess to rTMS may be limited, and it requires daily sessions for several weeks.
13
In adults with DTD, consider vagus nerve stimulation (VNS) as a third-line neuromodulation option.
Line / StrengthThird line
Level of EvidenceLevel 3
EvidenceSystematic reviews of open-label studies suggest longer-term treatment (2-5 years) with VNS results in superior response and remission rates compared to treatment-as-usual cohorts (Level 3). Short-term RCTs have not demonstrated efficacy.
For practiceReserve VNS for patients with difficult-to-treat depression who have failed other neuromodulation and pharmacological strategies, discussing the surgical nature and long-term benefit profile.
CaveatVNS involves surgical implantation and has lower evidence for efficacy and greater risks compared to noninvasive methods.
