1. Major Depression: This type of clinical Depression is characterized by a severe lack of interest in the things that were once enjoyed, or nonstop feelings of sadness.

2. Bipolar disorder or manic depressive illness: Also called Manic Depression, bipolar disorder is a type of depression that has either subtle or extreme “high” periods alternating with “low” periods of Depression.

3. Dysthymic disorder: This type of Depression is characterized by ongoing yet mild symptoms of Depression.

4. Cyclothymiacs disorder: is a relatively mild form of bipolar II disorder characterized by mood swings that may appear to be almost within the normal range of emotions. These mood swings range from mild depression, or dysthymia, to mania of low intensity, or hypomania.

5. Postnatal depression (PND) or Postpartum depression: is a complex mix of physical, emotional, and behavioral changes that occur in a mother after giving birth. It is a serious condition, affecting 10% of new mothers. Symptoms range from mild to severe Depression and may appear within days of delivery or gradually, perhaps up to a year later. Symptoms may last from a few weeks to a year.

6. Seasonal affective disorder (SAD): This type of depression occurs seasonally and is caused by lack of sunlight. What are the Symptoms of Depression?

Causes of Depression

There are a number of factors that may increase the chance of depression, among which they includes the following:

• Abuse. Past physical, sexual, or emotional abuse can cause depression later in life.

• Certain medications. Some drugs, such as Accutane (used to treat acne), the antiviral drug interferon-alpha, and corticosteroids, can increase your risk of depression.

• Conflict. Depression in someone who has the biological vulnerability to develop depression may result from personal conflicts or disputes with family members or friends.

• Death or a loss. Sadness or grief from the death or loss of a loved one, though natural, may increase the risk of depression.

• Genetics. A family history of depression may increase the risk. It's thought that depression is a complex trait that may be inherited across generations, although the genetics of psychiatric disorders are not as simple or straightforward as in purely genetic diseases such as Huntington's chorea or cystic fibrosis.

• Major events. Even good events such as starting a new job, graduating, or getting married can lead to depression. So can moving, losing a job or income, getting divorced, or retiring.

• Other personal problems. Problems such as social isolation due to other mental illnesses or being cast out of a family or social group can lead to depression.

• Serious illnesses. Sometimes depression co-exists with a major illness or is a reaction to the illness.

• Substance abuse. Nearly 30% of people with substance abuse problems also have major or clinical depression.

• Life events

Research suggests that continuing difficulties – long-term unemployment, living in an abusive or uncaring relationship, long term isolation or loneliness, prolonged exposure to stress at work – are more likely to cause depression than recent life stresses. However, recent events (such as losing a job) or a combination of events can ‘trigger' depression in people who are already at risk because of past bad experiences or personal factors. 

“Depression creates mental and physical symptoms in our thinking, feeling and bodily experience, as well as our behavior. These symptoms can vary from one person to another. Symptoms may change throughout the day, but are usually worse after waking up in the morning.