Major Depressive Disorder (MDD)

Definition:

Major Depressive Disorder is a mental health condition marked by persistent feelings of sadness, loss of interest, and impaired daily functioning for at least two weeks.

Causes:

• Genetic factors
• Chemical imbalances in the brain (especially serotonin, norepinephrine, dopamine)
• Stressful life events
• Medical conditions (e.g., thyroid disorders)
• Substance abuse

Symptoms:

• Persistent sadness or low mood
• Loss of interest in activities once enjoyed
• Fatigue and lack of energy
• Changes in appetite or weight
• Sleep disturbances (insomnia or hypersomnia)
• Feelings of worthlessness or guilt
• Difficulty concentrating
• Thoughts of death or suicide

Complications:

• Social withdrawal
• Poor performance at work or school
• Substance abuse
• Increased risk of suicide

Diagnosis:

• Clinical interview and symptom checklist (e.g., DSM-5 criteria)
• May include physical exams and lab tests to rule out other causes

Treatment:

• Antidepressant medications (e.g., SSRIs, SNRIs)
• Psychotherapy (especially CBT and interpersonal therapy)
• Lifestyle changes (exercise, sleep hygiene, social support)
• Electroconvulsive therapy (ECT) in severe cases