What is Major Depressive Disorder? Symptoms, Causes, Types and Treatment

What is Major Depressive Disorder Symptoms, Causes, Types and Treatment


What is Major Depressive Disorder? 

Major depressive disorder, also known simply as depression, is a common and serious mood disorder that causes severe symptoms and affects how you feel, think, and handle daily activities. To be diagnosed with depression, the symptoms must be present for at least two weeks. However, many people suffer from depression for many years if it is not treated. 


Symptoms of Depression

The most common symptoms of depression include:

  • Persistent sad, anxious, or "empty" mood.  
  • Feelings of hopelessness or pessimism.
  • Irritability, restlessness, or excessive crying.  
  • Loss of interest in activities or hobbies once pleasurable.  
  • Loss of energy or increased fatigue.
  • Difficulty concentrating, remembering details, or making decisions.
  • Insomnia, early-morning wakefulness, or excessive sleeping. 
  • Overeating, or appetite loss and unintended weight loss or gain.
  • Thoughts of death or suicide, or suicide attempts.
  • Aches or pains, headaches, cramps, or digestive problems without a clear physical cause and/or that do not ease even with treatment.

Causes of Depression

The exact cause of depression remains unknown, but it likely involves a combination of factors. 

Genes. Some people have a higher risk of depression if a parent or sibling has it.

Brain chemistry. Imbalances of neurotransmitters like serotonin and norepinephrine are thought to play a role.

Stressful life events. Trauma, loss, and difficult circumstances can trigger a depressive episode.

Chronic health problems. Depression is more common in people with chronic conditions.

Personality traits.  Some personality styles influence whether someone becomes depressed.

Substance use. Heavy alcohol use or drug abuse can cause or worsen feelings of depression.

Types of Depression

Major depressive disorder. This refers to periods lasting at least two weeks with symptoms affecting mood, thinking, behavior, and physical health.

Persistent depressive disorder.  A depressed mood that lasts for at least two years and occurs for more days than not. 

Perinatal depression. Depression during pregnancy or after childbirth that affects around 1 in 7 new mothers. 

Seasonal affective disorder. Symptoms of depression that coincide with changes in seasons, often in winter months. 

Psychotic depression. This type of major depression involves either hallucinations or delusions.  

Treatments for Depression

If you think you may have depression, visit your doctor or a mental health professional for an evaluation. Appropriate treatment can provide significant relief. Treatment options include:


Medication. Antidepressants target chemical imbalances in the brain that contribute to depression. These include SSRIs, SNRIs, and more.

Psychotherapy. Talk therapy helps identify and change negative patterns of thinking and behaving. Popular options are CBT and interpersonal therapy.

Lifestyle changes. Regular exercise, spending time with loved ones, and avoiding alcohol and drugs can give natural boosts to your mood.

Brain stimulation therapies. Options like transcranial magnetic stimulation (TMS) and electroconvulsive therapy (ECT) involve using magnetic fields or electric currents to stimulate nerve cells in the brain.  

Complementary therapies. Diet changes, herbal remedies, yoga, acupuncture and mindfulness practices can also help some people with depression.

If left untreated, major depression can worsen and become treatment resistant. Many who experience one episode of major depression have a high risk of future episodes. But with treatment and lifestyle changes, most people with depression can experience significant improvement and relief of symptoms. The sooner you seek treatment, the higher your chances of getting better.

In summary, major depressive disorder is a serious condition that causes many negative symptoms and impacts overall functioning. But appropriate evaluation and treatment can significantly improve the lives of those suffering from depression. If you think you may have depression, speak to your physician or a mental health professional as soon as possible. With the right help, you can feel better.