What is Depression?
Depression is a mental health disorder characterized by persistent sadness, lack of interest or pleasure, and a range of emotional and physical symptoms. It affects daily functioning, relationships, and overall quality of life. According to the World Health Organization (WHO), over 280 million people worldwide suffer from depression, making it a leading cause of disability globally.
Common Symptoms
- Persistent sadness or low mood
- Loss of interest in activities
- Changes in appetite or weight
- Sleep disturbances
- Fatigue or low energy
- Feelings of worthlessness or guilt
- Difficulty concentrating
- Thoughts of death or suicide
Types of Depression (Explained with Evidence)
1. Major Depressive Disorder (MDD)
Characterized by persistent low mood, fatigue, and disinterest in daily activities lasting at least two weeks. Affects ~8.3% of U.S. adults annually (NIMH). NIMH
2. Persistent Depressive Disorder (Dysthymia)
Chronic low-level depression lasting 2+ years. Often underdiagnosed yet impactful. Defined in DSM-5. Source: The Primary Care Companion to The Journal of Clinical Psychiatry
3. Bipolar Depression
Depressive episodes alternate with manic periods. Often more disabling than manic phases. Affects 45 million people globally (WHO). WHO
4. Seasonal Affective Disorder (SAD)
Depression triggered by seasonal light changes, especially in winter. Light therapy is highly effective. Source: Psychiatric Clinics of North America
5. Postpartum Depression (PPD)
Serious depression following childbirth. Affects 1 in 7 mothers (CDC). Differs from mild "baby blues". CDC
Summary Table
| Type | Key Features | Duration | Source |
|---|---|---|---|
| Major Depressive Disorder | Severe symptoms | ≥ 2 weeks | NIMH |
| Persistent Depressive Disorder | Chronic mild symptoms | ≥ 2 years | DSM-5 |
| Bipolar Depression | Alternates with mania | Episodic | WHO |
| Seasonal Affective Disorder | Seasonal onset | Winter/fall | Light therapy studies |
| Postpartum Depression | Post-birth depression | Weeks to months | CDC |
Causes and Risk Factors
- Genetics and family history
- Brain chemistry imbalances
- Trauma or abuse
- Chronic illness or medication
- Life stressors (loss, unemployment)
Treatment and Management
Depression is treatable with the right approach. Common options include:
- Psychotherapy (like Cognitive Behavioral Therapy)
- Medications (such as SSRIs)
- Lifestyle changes (exercise, diet, sleep)
- Support groups and family support
- Severe cases may require hospital care or brain stimulation techniques
When to Seek Help
If symptoms last more than 2 weeks, affect your work or relationships, or include suicidal thoughts, it’s time to seek help. In India, call iCall (022-25521111) or AASRA (91-22-27546669). In the U.S., call or text 988.
References
- WHO – WHO Depression Fact Sheet
- CDC – CDC Postpartum Depression
- NIMH – NIMH on Depression
- APA (DSM-5)
- Global Burden of Disease Study, The Lancet
- Psychiatric Clinics of North America