Depression: definition, statistics and types

Depression is a common medical illness that can disrupt your life.


  • Depression is characterized by a persistent low mood that is often accompanied by inability to feel pleasure. In addition, a person may have problems eating, sleeping, working, and getting along with his/her friends.
  • If such feelings linger for more than two weeks and start interfering with your daily activities, then you may be suffering from a clinical depression.
  • Depression is highly treatable. People often respond well to available treatments, but no known cure exists.
  • Major depressive disorder is a mood disorder that cause people to feel severe depressive mood along with several other symptoms that occur nearly everyday during the depressive episode. Depressive episodes can last 2 weeks or longer when untreated.

How common is depression?

According to the Center for Disease Control and Prevention 7.06% of the entire US adult population during the period of 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 have 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.
  • Around 50% of those suffering from a 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 a normal life. People may have depressive episodes that can last weeks to months and may have such episodes multiple times in their life.
  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 2 years.
  3. Psychotic depression – This is a form of severe major depression that is accompanied by psychosis (psychosis is a condition in which a person loses contact with reality or is unable to think in an organized way).
  4. Postpartum depression – Many mothers experience “baby blues” during the first week or two after childbirth; but postpartum depression lasts longer 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% 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 amount of disruption this illness can cause.
  7. Atypical depression – This is a subtype of major depression which involves increased fatigue, sleepiness, weight gain and/or increased appetite. It usually affects people at an early age, particularly 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?

  1. Depressed mood which can include crying spells, feeling hopeless
  2. Little interest or pleasure in all activities including those you once enjoyed
  3. Decrease in appetite or overeating which can result in weight loss without dieting or weight gain
  4. Poor sleep or sleeping too much
  5. Feeling restless or being slowed down
  6. Fatigue or loss of energy
  7. Feeling like a failure or excessive guilt and a sense of worthlessness
  8. Difficulty in concentrating or thinking or making decisions
  9. Frequent thoughts of death or thoughts of suicide.
These symptoms interfere with the function of people struggling from depression and depressive episodes can reoccur.

What causes depression?

Depression can be a result of several factors. Our brains produces chemical substances known as neurotransmitters that are released by nerves in the brain. These neurotransmitters help cells in the brain communicate with each other. One of the factors that can lead to depression is the imbalance of these chemicals. Another factor we have learned from brain imaging research is the physical changes that occur in the brain impacting the 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 make up. 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.

Treatment for Depression

Treatment options for depression include medication, talk therapy known as psychotherapy, and transcranial magnetic stimulation (TMS) therapy. If you are having any of these symptoms, reach out to a doctor or mental health clinician.

Concluding words of wisdom

Clinical depression can affect any one 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 be of immense help in providing non-judgmental and empathic support. Hence, with a good support network and good psychiatric care, many people who suffer from this illness can and DO lead normal and meaningful lives.

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