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Depression: definition, statistics, and Types

Depression is one of the common mental disorders that can disrupt your life.


  • Depression is a mental health disorder characterized by a persistently low mood, often accompanied by an inability to feel pleasure. In addition, a person may have problems eating, sleeping, working, and getting along with friends.
  • If such feelings linger over two weeks and start interfering with your daily activities, you may suffer from clinical depression.
  • Depression is highly treatable. People often respond well to available treatments, but no known cure exists.
  • Major depressive disorder, or MDD, is a mood disorder that causes people to feel severe depressive moods along with several other mental and physical symptoms that occur nearly every day during the depressive episode. Depressive episodes can last two weeks or longer when untreated.

How Common is Depression?

According to the Centers for Disease Control and Prevention, 7.06% of the US adult population from 2009 to 2012 suffered from depression.


  • According to the World Health Organization (WHO), 350,000,000 people are affected by depression worldwide.
  • In the US, approximately 16,000,000 adults reportedly suffered from at least one major depressive episode (MDE) in 2012 alone. That is around 6.9 percent of the country’s total population.
  • depressive episode (MDE) in 2012 alone. That is around 6.9 percent of the country’s total population.
  • Around 50% of those suffering from clinical depression do not seek medical treatment.
  • According to the Centers for Disease Control, 41,149 suicides were reported in 2013. Therefore, the ratio of suicide deaths per 100,000 people is 13:100,000.

Types of Depression

  1. Major depression – Symptoms include interference with your capacity to sleep, work, eat, or enjoy everyday life. People may have depressive episodes that can last weeks to months and may have such episodes multiple times.
  2. Persistent depressive disorder – Previously known as dysthymia, this is a form of chronic depression with symptoms less severe but longer lasting than major depression. This form of depression may last as long as two years.
  3. Psychotic depression – This is a form of severe major depression that is accompanied by psychosis (a condition in which a person loses contact with reality or is unable to think in an organized way).
  4. Perinatal depression – Many mothers experience “baby blues” during the first week or two after childbirth. Still, postpartum depression persists and is more intense than baby blues and eventually interferes with your ability to care for your baby and handle other daily tasks. Around 10-15% of mothers have postpartum depression after delivering a child.
  5. Seasonal affective disorder (SAD) – This is a type of depression in which people experience depressive symptoms primarily during the winter seasons.
    • This kind of depression can be effectively treated with light therapy.
    • In addition to light therapy, antidepressant medication and psychotherapy may also be helpful.
  6. Bipolar disorder – Bipolar disorder is characterized by extreme mood changes, including emotional lows (depression) and highs (mania or hypomania), that last for at least a few weeks at a time and may recur throughout the year. Bipolar disorder can be disruptive in many cases, and psychological counseling and medications can help minimize the disruption this illness can cause.
  7. Atypical depression – This is a subtype of major depression that involves increased fatigue, sleepiness, weight gain, and/or increased appetite. It usually affects people at an early age, mainly when they are in their teens.
  8. Premenstrual dysphoric disorder (PDD) – This is regarded as a severe form of premenstrual syndrome (PMS). It usually occurs in the second half of a woman’s menstrual cycle, especially during the days before the onset of the menstrual period.

What are the Symptoms of Depression?

Symptoms of depression for adults:

  • Depressed mood, which may include tears and a sense of hopelessness.
  • Little enjoyment or interest in all activities, even those you used to enjoy.
  • Without dieting or weight gain, weight loss can occur as a result of an increase in appetite or overeating.
  • Getting too little or too much sleep.
  • Feeling impatient or slowed down.
  • Fatigue or a decrease in energy.
  • Excessive guilt, a sense of worthlessness, or a sense of failure.
  • Inability to focus, think clearly, or make decisions.
  • Frequently having suicidal thoughts.

Symptoms of depression for children:

  • Depression in young children can manifest as sadness, irritability, clinginess, worry, aches and pains, refusal to attend school, or being underweight.
  • Teens may experience symptoms such as sadness, irritability, feeling down and unworthy, anger, poor performance or poor attendance at school, feeling misunderstood and overly sensitive, using alcohol or drugs recreationally, eating excessively, engaging in self-harm, losing interest in regular activities, and avoiding social interaction.

Symptoms of depression for older adults:

  • Memory issues or character changes.
  • Physical discomfort.
  • Symptoms of exhaustion, anorexia, insomnia, or loss of interest in sex are not brought on by a disease or medication.
  • Frequently preferring to stay in rather than leave the house to interact with others or try new things.
  • Especially in older men with suicidal thoughts or feelings.

What Causes Depression?

Depression can be a result of several factors. Our brains produce chemical substances known as neurotransmitters released by nerves in the brain. These neurotransmitters help cells in the brain communicate with each other. One of the factors that can cause depression is the imbalance of these chemicals.

Another factor we have learned from brain imaging research is the physical changes in the brain, impacting several parts of the brain. These brain structures are involved in experiencing emotion, decision-making, reward anticipation, attention, memory, and motivation. Changes in our hormones can have a significant impact on depression.

These changes can be influenced by highly stressful events and even our genetic makeup. People who have 1st-degree relatives that suffer from depression have a higher likelihood of having depression.

Other medical conditions like diabetes, heart disease, cancer, chronic pain, and inflammation can also lead to depression.


Events or circumstances that are emotional, psychological, or physical triggers can bring on or exacerbate depression symptoms.

Some of the triggers include these:

  • Stressful life circumstances, including bereavement, family disputes, and relationship changes.
  • Incomplete recovery after prematurely discontinuing depression treatment.
  • Medical conditions, particularly a medical emergency like a new diagnosis or a chronic illness like diabetes or heart disease.

Risk Factors

Depression is more likely to affect some people than others due to the presence of certain risk factors, like:

  • Experiencing certain life events, such as a death in the family, problems at work, relationship changes, money troubles, and health issues. Severe stress.
  • Not having any effective coping mechanisms.
  • Having a close family member who is depressed.
  • Using prescription medications such as corticosteroids, specific beta-blockers, and interferon.
  • Using alcohol or illicit drugs like amphetamines for recreation.
  • Suffering a head injury.
  • Having a neurodegenerative condition like Parkinson’s or Alzheimer’s.
  • Having experienced a major depressive episode in the past.
  • Having a long-term illness, such as diabetes, cardiovascular disease, or chronic obstructive pulmonary disease (COPD).
  • Suffering from persistent pain.
  • Inadequate social support.

Is it Time to See a Mental Health Professional?

If you’re experiencing most of these symptoms of a depressive disorder on most days, speak up to your doctor.

If you’re hesitant to get help, talk to a friend or family member, a doctor, a member of your faith community, or someone else you can trust.

Depression Diagnosis

Your physician might identify you as having depression based on the following:

  • Physical Exam – Your physician might conduct a physical examination and inquire about your health. Sometimes a physical health issue may be the underlying cause of depression.
  • Lab Test – For instance, your doctor might check your thyroid to see if it is functioning correctly or perform a blood test called a complete blood count.
  • Psychiatric Evaluation – Your mental health professional will enquire about your signs, patterns of thought and behavior, and feelings. To assist in addressing these inquiries, you might be asked to complete a questionnaire.
  • DSM-5 – The Diagnostic and Statistical Manual of Mental Disorders, aka the DSM-5, published by the American Psychiatric Association, may be used by your mental health professional to determine whether you meet the criteria for depression.

Treatment for Depression

However, 30.9% of patients either do not respond to treatment or do not respond well. About 4 out of 10 people experience a remission of their symptoms within a year, but depression can recur.

Symptom management typically consists of three steps:

  • Support: This can include educating family members and talking about real-world solutions and potential causes.
  • Psychotherapy: It is also referred to as talking therapy and includes options like cognitive behavioral therapy (CBT) and one-on-one counseling.
  • Antidepressants: Antidepressants are a standard drug treatment option.
  • TMS Therapy: Transcranial magnetic stimulation (TMS) is a noninvasive procedure that helps improve symptoms of depression. TMS is usually used when other depression treatments fail to provide positive results.

How Can You Keep Your Depression in Check?

There are various ways to keep depression in check. Here are some tips that may help:

  1. Exercise regularly
  2. Cut back on social media time
  3. Build strong relationships
  4. Minimize your daily choices
  5. Reduce stress
  6. Maintain your treatment plan
  7. Get plenty of sleep
  8. Stay away from toxic people

Depression FAQs

Does depression go away on its own? ︿

Mild depression, like seasonal affective depression (e.g., the winter blues), can go away on its own without lasting long. If your depression is the reason for a specific situation or temporary stressor, it may also not last long. But in the case of severe depression, symptoms last for years and don’t go away on their own.

Of course, it’s not impossible for an episode of depression to go away on its own if given time, but reaching out for help can get you feeling better faster.

Does depression make you tired?

Can depression cause memory loss?

How to deal with your depressive episode?

How to get motivated when depressed?

Is not dreaming a sign of depression?

Is major depressive disorder a disability?

What should you not say to someone with depression?

Is depression a choice?

Can patients with depression develop anxiety disorders?


Clinical depression can affect anyone of any age, including children. But with proper psychological counseling, administration of antidepressant medications, or both, symptoms of clinical depression can be effectively treated.

Family and friends can immensely help provide non-judgmental and empathic support. Hence, with a good support network and good psychiatric care, many people suffering from this illness can and DO lead meaningful daily lives.

Best depression psychiatrists near me

Dr. Joann Mundin, MD Psychiatrist

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Dr. Phacharawut Kanchan, MD Psychiatrist

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