Understanding Depression: Symptoms, Causes & Treatment
Comprehensive guide to major depressive disorder: what it is, what causes it, how it's diagnosed, and evidence-based treatment options.
Clinically Reviewed: Board-Certified Psychiatrist |Next Review: September 2025
Key Takeaways
- Depression is a medical condition involving brain chemistry, not a character flaw or weakness
- Affects 21+ million American adults; highly treatable with multiple evidence-based options
- Symptoms include persistent sad mood, loss of interest, energy changes, sleep/appetite disruption
- Biological, psychological, and social factors all contribute to depression
- Treatment options include therapy, medication, TMS, and lifestyle interventions
Symptoms of Depression
Core symptoms (need 5+ for 2+ weeks for diagnosis):
- Depressed mood most of the day
- Loss of interest or pleasure in activities
- Significant weight/appetite changes
- Insomnia or sleeping too much
- Restlessness or slowed movements
- Fatigue or low energy
- Feelings of worthlessness or guilt
- Difficulty concentrating or making decisions
- Thoughts of death or suicide
Treatment Options
- Psychotherapy: CBT, IPT, behavioral activation
- Medications: SSRIs, SNRIs, bupropion, others
- TMS: Brain stimulation for treatment-resistant depression
- Lifestyle: Exercise, sleep, social connection, nutrition
- Comprehensive care: Combining multiple approaches
Frequently Asked Questions
What causes depression?
Depression results from complex interaction of biological factors (genetics, brain chemistry), psychological factors (thinking patterns, trauma history), and social factors (stress, relationships, life events). It's not caused by one thing and isn't your fault.
Is depression the same as sadness?
No. Sadness is a normal emotion that comes and goes. Depression is persistent (2+ weeks), affects functioning, includes multiple symptoms (not just sad mood), and doesn't improve with positive events. Depression is a medical condition requiring treatment.
Can depression be cured?
Depression is treatable, and many people fully recover. However, it can be recurrent—about 50% of people who have one depressive episode will have another. Ongoing management (maintenance medication, therapy check-ins, lifestyle) helps prevent relapse.
What if I'm depressed but don't feel sad?
Some people experience depression as numbness, emptiness, irritability, or loss of interest rather than sadness. Physical symptoms (fatigue, aches, sleep/appetite changes) may be more prominent. This is still depression and still treatable.
How long does depression last?
Untreated, major depressive episodes average 6-8 months but can persist longer. With treatment, most people see significant improvement within 8-12 weeks. Early intervention shortens episodes and improves outcomes.
Can depression come back after treatment?
Yes, depression can recur. Risk factors include stopping treatment prematurely, high life stress, previous multiple episodes. Maintenance treatment (staying on medication longer, periodic therapy check-ins) reduces recurrence risk.
References
- 1. American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.).
- 2. National Institute of Mental Health. "Major Depression." NIMH Statistics