Depression.

Major depressive disorder requires at least five DSM-5 symptoms for at least two weeks, including persistently low mood or loss of interest, plus combinations of sleep disturbance, appetite or weight change, fatigue, slowed thinking, feelings of worthlessness or guilt, poor concentration, and thoughts of death or suicide. Symptoms cause distress or interfere with work, school, or relationships.

Sadness is a normal emotion in response to loss or disappointment, usually time-limited and proportional. Depression is a sustained illness lasting at least two weeks that interferes with sleep, energy, appetite, concentration, and self-worth, and may include thoughts of death. Sadness is part of being human; depression is a treatable medical condition.

Depression is a clinical diagnosis based on DSM-5-TR criteria gathered through interview and supported by the PHQ-9 self-report. A PHQ-9 score of 10 or higher has 88% sensitivity for major depressive disorder. Basic labs (thyroid, CBC, B12, vitamin D) exclude medical mimics, and patients are screened for bipolar disorder, anxiety, and substance use that change treatment.

Sleep, appetite, and energy can improve within 1-2 weeks of starting an SSRI or SNRI. Mood typically responds at 2-4 weeks and full response by 6-8 weeks. If there is no meaningful improvement by week 4 at adequate dose, your clinician may increase the dose, switch agents, or add augmentation.

Antidepressants are not addictive in the way that opioids, stimulants, or alcohol are — they do not cause craving or compulsive use, and they have no street value. Discontinuation symptoms can occur if certain antidepressants are stopped abruptly, which is why they should be tapered over weeks rather than stopped suddenly.

For mild depression, evidence-based psychotherapy (CBT, IPT, behavioral activation) is first-line. For moderate-to-severe MDD, combined therapy plus an SSRI or SNRI outperforms either alone. Severe, psychotic, or treatment-resistant depression responds best to ECT, ketamine/esketamine, or rTMS. Treatment is individualized based on severity, history, and patient preference.

A single depression episode can fully resolve with treatment, and many people recover completely. Recurrence is common — 50% after one episode, 70% after two, 90% after three. Continuation therapy for 6-9 months after remission, and maintenance therapy after multiple episodes, substantially reduces recurrence.

Heritability for major depressive disorder is roughly 30-40%, higher for early-onset and recurrent forms. First-degree relatives have 2-3× the population risk. Genes interact with environmental factors — childhood adversity, stress, and medical illness — so genetics alone do not predict who will become depressed.

Treatment-resistant depression is the failure to respond to two adequate trials of different first-line antidepressants. It affects about 30% of patients with major depressive disorder. Effective options include esketamine nasal spray, IV ketamine, electroconvulsive therapy (ECT), repetitive transcranial magnetic stimulation (rTMS), and lithium or atypical antipsychotic augmentation.

The PHQ-9 is a nine-item self-report questionnaire that measures depression severity. Each item is scored 0-3 based on frequency over the prior two weeks; total scores range from 0-27. Scores 5-9 indicate mild, 10-14 moderate, 15-19 moderately severe, and 20+ severe depression. It is the standard tool for screening and tracking treatment response.

Yes. Common physical features include fatigue, appetite or weight change, sleep disturbance, slowed movement, headaches, GI complaints, and chronic pain. In many primary-care visits, especially in older adults and across many cultures, physical symptoms are the presenting complaint and depression is the underlying diagnosis.

Yes. Aerobic exercise of 30-45 minutes 3-5 times per week is roughly equivalent to a low-dose antidepressant in mild-to-moderate depression. Meta-analyses in JAMA Psychiatry and Cochrane confirm clinically meaningful effects. Exercise also helps treatment-resistant cases when added to medication and therapy.

Postpartum depression is major depressive disorder with onset during pregnancy or in the year after birth. It affects 10-15% of mothers and about 10% of fathers. Distinct neuroendocrine drivers make it responsive to brexanolone (IV) and zuranolone (oral), in addition to standard antidepressants and therapy.

Risk can be reduced. Treating chronic insomnia, regular aerobic exercise, addressing substance use, maintaining social connection, treating chronic medical illness, and brief preventive psychotherapy after major life stressors all lower incidence. People with prior episodes can prevent recurrence with maintenance antidepressant therapy and mindfulness-based cognitive therapy.

Light occasional drinking is generally acceptable, but heavy alcohol use blunts antidepressant response, worsens mood, increases sedation, and raises suicide risk. During acute treatment most clinicians recommend minimizing or avoiding alcohol entirely, particularly in the first 8-12 weeks.

Yes. Major depressive disorder occurs in 1-2% of children and 4-8% of adolescents. Symptoms can include irritability rather than sadness, school decline, and physical complaints. First-line treatment is psychotherapy (CBT or IPT); fluoxetine and escitalopram are the SSRIs with the strongest pediatric evidence, used with careful suicidality monitoring.

Electroconvulsive therapy is a treatment in which a brief electric current induces a generalized seizure under general anesthesia. It is used for severe, psychotic, catatonic, or treatment-resistant depression. Remission rates are 60-80% — the highest of any treatment. Modern ECT is safe with transient memory side effects.

988 is the US Suicide & Crisis Lifeline. Calling or texting 988 connects you to free, confidential 24/7 support from trained crisis counselors. The lifeline is for anyone in suicidal crisis, emotional distress, or concern about a loved one. International equivalents exist; search for your country's crisis line.

Yes. Concentration impairment, slowed thinking, and difficulty making decisions are core symptoms of depression. In older adults, depression can mimic dementia (pseudo-dementia); cognitive symptoms improve substantially with successful treatment of the depression. Persistent memory loss after recovery warrants neurologic evaluation.

No, not without talking to your clinician. Stopping too early triples the relapse risk in the first six months. Continuation therapy for at least 6-9 months after remission is standard; people with three or more lifetime episodes are often advised to continue indefinitely. Any discontinuation should be tapered, not abrupt.

Aerobic exercise, bright-light therapy (especially for seasonal pattern), CBT, mindfulness-based cognitive therapy, and Mediterranean-style eating have evidence for mild-to-moderate depression. St. John's wort has European evidence for mild MDD but interacts with many medications. For moderate or severe depression, these are adjuncts to, not substitutes for, professional treatment.