Major Depressive Disorder: Diagnosis, SSRI Management, and Suicide Risk Assessment

Major Depressive Disorder (MDD) is diagnosed using DSM-5-TR criteria, requiring at least 5 symptoms present for ≥2 weeks, with at least one being depressed mood or anhedonia.

🔑 KEY CONCEPT: The SIG-E-CAPS mnemonic helps remember core symptoms:

• Sleep disturbances (insomnia or hypersomnia)
• Interest/pleasure loss (anhedonia)
• Guilt or worthlessness
• Energy loss/fatigue
• Concentration difficulties
• Appetite changes (increase or decrease)
• Psychomotor agitation or retardation
• Suicidal ideation

⚡ HIGH-YIELD: Differential diagnosis must exclude:

• Bipolar disorder (screen for manic/hypomanic episodes)
• Medical conditions (hypothyroidism, anemia, sleep apnea)
• Substance-induced mood disorder
• Adjustment disorder with depressed mood

Severity Assessment Tools:

• PHQ-9 (Patient Health Questionnaire-9): Scores 5-9 (mild), 10-14 (moderate), 15-19 (moderately severe), 20-27 (severe)
• Hamilton Depression Rating Scale (HAM-D): Professional assessment tool
• Beck Depression Inventory-II (BDI-II): Self-report measure

⚠️ PEARL: Always assess for psychotic features in severe depression, as this significantly impacts treatment approach and prognosis. Psychotic depression requires combination antidepressant-antipsychotic therapy or ECT.

Selective Serotonin Reuptake Inhibitors (SSRIs) are first-line treatment for MDD, working by blocking serotonin reuptake at presynaptic terminals, increasing synaptic serotonin availability.

🔑 KEY CONCEPT: All SSRIs have similar efficacy (~60-70% response rate), but differ in side effect profiles, drug interactions, and half-lives.

Selection Considerations:

• Fluoxetine: Best for patients with fatigue, weight gain concerns
• Sertraline: Preferred in cardiac patients, fewer interactions
• Paroxetine: Avoid in elderly due to anticholinergic effects
• Escitalopram: Often best tolerated, good first choice

⚡ HIGH-YIELD: SSRI onset of action:

• Neurochemical changes: Hours to days
• Clinical improvement: 2-4 weeks
• Full therapeutic effect: 6-8 weeks

Common Side Effects:

• Early: Nausea, headache, diarrhea, insomnia
• Ongoing: Sexual dysfunction (70% of patients), weight gain
• Withdrawal: Discontinuation syndrome with short half-life agents

⚠️ PEARL: Start with low doses in elderly patients (reduce by 50%) and those with hepatic impairment. Monitor for hyponatremia, especially in elderly patients on diuretics.

Suicide risk assessment is critical in MDD management, as 15% of patients with severe depression die by suicide. Systematic evaluation using validated tools and clinical judgment is essential.

🔑 KEY CONCEPT: The SAD PERSONS scale provides structured risk assessment:

• Sex (male higher risk)
• Age (<19 or >45 years)
• Depression/hopelessness
• Previous attempts
• Ethanol abuse
• Rational thinking loss
• Social support lacking
• Organized plan
• No spouse/significant other
• Sickness/serious illness

Risk Stratification Framework:

LOW RISK (Score 0-3): → Outpatient management → Safety planning → Close follow-up

MODERATE RISK (Score 4-6): → Consider hospitalization → Remove means → Intensive monitoring

HIGH RISK (Score 7-10): → Immediate hospitalization → 1:1 observation → Emergency psychiatric consultation

⚡ HIGH-YIELD: Direct questioning about suicidal ideation does NOT increase suicide risk. Always ask:

1. "Have you had thoughts of hurting yourself?"
2. "Do you have a plan?"
3. "Do you have access to means?"
4. "What stops you from acting on these thoughts?"

Warning Signs Requiring Immediate Action:

• Specific suicide plan with high lethality means
• Recent rehearsal behaviors
• Severe hopelessness or agitation
• Command auditory hallucinations
• Recent significant loss or humiliation

Protective Factors:

• Strong social support system
• Religious/spiritual beliefs
• Responsibility for children
• Pregnancy
• Future-oriented thinking

⚠️ PEARL: Paradoxical increase in suicide risk may occur early in SSRI treatment (first 2-4 weeks) due to improved energy before mood improvement, particularly in patients <25 years old.

Comprehensive medical evaluation is essential to rule out organic causes of depression and establish baseline parameters before initiating treatment.

Essential Laboratory Tests:

Additional Considerations:

• Folate: 10-45 nmol/L (deficiency in alcoholism, malnutrition)
• Magnesium: 0.75-1.25 mmol/L (hypomagnesemia causes mood changes)
• Cortisol: Consider dexamethasone suppression test if Cushing's suspected

🔑 KEY CONCEPT: The dexamethasone suppression test can help differentiate severe depression from Cushing's syndrome:

• Normal: Cortisol suppression <138 nmol/L after 1mg dexamethasone
• Depression: May have non-suppression (false positive in 50%)
• Cushing's: Consistent non-suppression

Cardiac Considerations for SSRI Therapy:

• Baseline ECG for patients >50 years or cardiac risk factors
• QTc monitoring with citalopram (max 40mg if >60 years)
• Escitalopram preferred in cardiac patients

Drug Screening Indications:

• Unexplained mood changes
• Treatment-resistant depression
• Comorbid substance use suspected
• Adolescent/young adult patients

⚡ HIGH-YIELD: Always check drug interactions before prescribing SSRIs:

• MAOIs: 2-week washout required (5 weeks for fluoxetine)
• Warfarin: Increased bleeding risk
• NSAIDs: GI bleeding risk
• Tramadol: Serotonin syndrome risk

⚠️ PEARL: In elderly patients, check sodium levels 1-2 weeks after SSRI initiation, as SIADH is more common in this population.

Proper SSRI dosing and titration strategies maximize therapeutic benefit while minimizing adverse effects. Most patients require adequate doses for sufficient duration.

Standard Dosing Protocols:

*Reduced to 20mg in patients >60 years due to QTc prolongation risk

🔑 KEY CONCEPT: "Start low, go slow" approach:

• Begin with standard starting dose
• Assess response at 2-4 weeks
• Increase dose if partial response and tolerated
• Allow 6-8 weeks at therapeutic dose before considering switch

Titration Timeline:

Weeks 1-2: Monitor side effects, provide support Weeks 3-4: Assess early response, adjust dose if needed Weeks 5-8: Evaluate full therapeutic response Weeks 8-12: Optimize dose or consider alternatives

Dose Optimization Strategies:

• Partial Response: Increase dose to maximum tolerated
• No Response: Consider medication switch or augmentation
• Side Effects: Reduce dose, switch to different SSRI, or add adjunctive treatment

⚡ HIGH-YIELD: Response vs. Remission:

• Response: ≥50% reduction in depression rating scale scores
• Remission: Minimal residual symptoms (PHQ-9 <5, HAM-D <7)
• Recovery: Sustained remission for ≥6 months

Special Populations:

• Elderly: Start with 50% of adult dose
• Hepatic impairment: Reduce dose, avoid paroxetine
• Renal impairment: No dose adjustment needed for most SSRIs
• Pregnancy: Sertraline preferred; avoid paroxetine (cardiac defects)

Managing Common Side Effects:

• Sexual dysfunction: Dose reduction, drug holiday, bupropion addition
• Weight gain: Lifestyle counseling, consider switching to fluoxetine
• Insomnia: Take morning dose, sleep hygiene, short-term trazodone
• GI upset: Take with food, probiotics, temporary dose reduction

⚠️ PEARL: If switching SSRIs due to inefficacy, direct switch is usually safe (except with fluoxetine's long half-life). Cross-titration may reduce discontinuation symptoms.

Treatment-resistant depression (TRD) affects 30-40% of MDD patients and requires systematic approach including medication optimization, augmentation, or alternative treatments.

🔑 KEY CONCEPT: TRD definition:

• Failure to respond to ≥2 adequate antidepressant trials
• Each trial: Therapeutic dose for ≥6 weeks
• Good medication adherence confirmed

Systematic Approach to TRD:

STEP 1: Optimize current SSRI → Maximize dose if tolerated → Ensure adequate duration (8-12 weeks) → Address adherence issues

STEP 2: Switch within class or between classes → SSRI to SNRI (venlafaxine, duloxetine) → Consider atypical agents (bupropion, mirtazapine)

STEP 3: Augmentation strategies → Atypical antipsychotics → Lithium → Thyroid hormone

STEP 4: Alternative treatments → ECT, TMS, ketamine

Evidence-Based Augmentation Options:

⚡ HIGH-YIELD: FDA-approved augmentation agents:

• Aripiprazole (most evidence)
• Quetiapine XR
• Olanzapine/fluoxetine combination
• Brexpiprazole

Monitoring for Augmentation Therapy:

• Atypical antipsychotics: Baseline and follow-up metabolic panel, weight, waist circumference, blood pressure
• Lithium: Levels (0.6-1.0 mEq/L), creatinine, TSH, CBC
• T3: TSH, free T4, cardiac monitoring in elderly

Alternative Treatment Considerations:

• ECT: Most effective for severe, psychotic, or catatonic depression
• TMS: FDA-approved for TRD, minimal side effects
• Ketamine/esketamine: Rapid-acting, for severe TRD with suicidal ideation
• Psychotherapy: CBT, IPT, especially effective when combined with medication

Combination Antidepressants:

• Bupropion + SSRI: Addresses sexual dysfunction, weight gain
• Mirtazapine + SSRI: "California rocket fuel" - monitor for serotonin syndrome
• Vortioxetine + SSRI: Limited evidence, cognitive benefits

⚠️ PEARL: Before diagnosing TRD, ensure medication adherence, adequate dosing, sufficient duration, and rule out comorbid conditions (anxiety disorders, substance use, medical conditions) that may impact treatment response.

Long-term management of MDD focuses on maintaining remission, preventing relapse/recurrence, and optimizing functional recovery through continued pharmacotherapy and psychosocial interventions.

Phases of Depression Treatment:

🔑 KEY CONCEPT: Maintenance therapy duration depends on episode history:

• First episode: 6-12 months after remission
• Second episode: 1-2 years minimum
• Three or more episodes: Consider indefinite treatment
• High-risk factors: Indefinite treatment recommended

High-Risk Factors for Recurrence:

• Early onset (<20 years)
• Family history of mood disorders
• Severe episodes or psychotic features
• Comorbid anxiety/substance use disorders
• Chronic medical conditions
• Poor social support
• Residual symptoms

Monitoring During Maintenance:

• Monthly visits initially, then every 3-6 months
• PHQ-9 scores at each visit
• Functional assessment (work, relationships, activities)
• Side effect monitoring (weight, sexual function, sleep)
• Laboratory monitoring as indicated by medication

⚡ HIGH-YIELD: Discontinuation syndrome prevention:

• Taper gradually over 2-4 weeks minimum
• Slower taper for short half-life agents (paroxetine, venlafaxine)
• Monitor for flu-like symptoms, "brain zaps", dizziness
• Consider switching to fluoxetine before discontinuation

Psychosocial Interventions:

• Cognitive Behavioral Therapy (CBT): Reduces relapse risk by 50%
• Interpersonal Therapy (IPT): Effective for relationship issues
• Mindfulness-Based Cognitive Therapy (MBCT): Prevents depressive rumination
• Lifestyle modifications: Regular exercise, sleep hygiene, stress management

Breakthrough Episodes Management:

Mild breakthrough symptoms: → Assess stressors and adherence → Consider brief therapy intensification → Increase monitoring frequency

Moderate-severe breakthrough: → Medication dose increase → Add augmentation agent → Consider hospitalization if severe

Special Considerations:

• Seasonal pattern: Light therapy, seasonal medication adjustments
• Pregnancy planning: Medication risk-benefit analysis, preconception counseling
• Elderly patients: More frequent monitoring, fall risk assessment
• Adolescents: Family involvement, school performance monitoring

⚠️ PEARL: Patients achieving remission should continue antidepressant at the same dose that achieved remission. Dose reduction increases relapse risk significantly. Regular psychiatric follow-up improves outcomes and medication adherence.