- MDD is the #3 cause of the burden of disease worldwide (WHO, 2008)
Depressive disorders:As per diagnostic Statistical Manual of Mental Disorders, fifth Edition (DSM-5)
- Persistent depressive disorder (formerly known as dysthymia)
- Disruptive mood dysregulation disorder
- Premenstrual dysphoric disorder
- Substance/medication-induced depressive disorder
- Depressive disorder due to another medical condition
- Unspecified depressive disorder
The etiology of major depressive disorder is multifactorial with both genetic and environmental factors playing a role. First-degree relatives of depressed individuals are about 3 times as likely to develop depression as the general population; however, depression can occur in people without family histories of depression.
- Female gender
- History of anxiety
- History of eating disorders
- First-degree relative with a history of depression
- History of or current drug or alcohol abuse
- History of or current sexual abuse or domestic violence
Co-morbidities:patients with major medical conditions or with chronic medical conditions are at a greater risk of experiencing depressive symptoms.
- Cardiac illnesses: Myocardial infarction, coronary artery atherosclerotic disease, and arrhythmias
- Cerebrovascular disease (after a stroke or a transient ischemic attack)
- Chronic lung/renal disease
- Chronic pain disorders
- Structural MRI: Reduction in volume of cingulate cortex, prefrontal cortex, amygdala and hippocampus
- Functional MRI:
- Compromised function in prefrontal area during cognitive task
- Hyperactivity of limbic system during an emotional task
Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) diagnostic criteria:Individual must have 5 symptoms, of which one must be a depressed mood or anhedonia causing social or occupational impairment, to be diagnosed with MDD.
- Persistently low or depressed mood
- Anhedonia (decreased interest in previously pleasurable activities)
- Feelings of guilt or worthlessness
- Lack of energy
- Poor concentration
- Appetite changes
- Psychomotor retardation/agitation
- Sleep disturbances
- Suicidal thoughts
Major depressive disorder is a clinical diagnosis; it is mainly diagnosed by the clinical history given by the patient and mental status examination. The clinical interview must include medical history, family history, social history, and substance use history along with the symptomatology. Collateral information from a patient’s family/friends is a very important part of psychiatric evaluation.
- Patient Health Questionnaire-9 (PHQ-9): Self-report, standardized depression rating scale is commonly used for screening, diagnosing, and monitoring treatment response for MDD
- Hamilton Rating Scale for Depression (HAM-D) (hospital settings): Clinician-administered depression rating scale is commonly used for the assessment of depression
- Other scales:
- Montgomery-Asberg Depression Rating Scale (MADRS)
- Beck Depression Inventory (BDI)
- Zung Self-Rating Depression Scale
- Raskin Depression Rating Scale
- Ask Suicide-Screening Questions
Stepped-care model:The initial treatment of MDD includes medications or/and psychotherapy. Combination treatment, including both medications and psychotherapy, has been found to be more effective than either of these treatments alone. Electroconvulsive therapy is found to be more efficacious than any other form of treatment for severe major depression.
- Selective serotonin reuptake inhibitors (SSRIs): First-line for late-onset depression
- Citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, vilazodone, vortioxetine
- Serotonin/norepinephrine reuptake inhibitors (SNRIs): In patients non-responsive to SSRIs and first-line agents in cases with significant fatigue/pain syndromes associated with depression
- Venlafaxine, desvenlafaxine, duloxetine, and levomilnacipran
- Atypical antidepressants: Bupropion, mirtazapine, nefazodone, and trazodone
- Serotonin-Dopamine Activity Modulators (SDAMs): Partial agonist at 5-HT1A and dopamine D2 receptors at similar potency, and as an antagonist at 5-HT2A and noradrenaline
- Brexpiprazole and aripiprazole
- Tricyclic antidepressants (TCAs): Amitriptyline, clomipramine, desipramine, doxepin, imipramine, nortriptyline, protriptyline, trimipramine
- Monoamine oxidase inhibitors (MAOIs): Isocarboxazid, phenelzine, selegiline, and tranylcypromine
Electroconvulsive therapy (ECT):Treatment of choice for patients who do not respond to drug therapy, are psychotic, or are suicidal or dangerous to themselves.
- Cognitive behavior therapy (CBT): Structured, and didactic form of therapy that focuses on helping individuals identify and modify maladaptive thinking and behavior patterns (16-20 sessions).
- Interpersonal therapy: Time-limited (typically 16 sessions) treatment for major depressive disorder which draws from attachment theory and emphasize the role of interpersonal relationships, focusing on current interpersonal difficulties.