There are several forms of depression. Below are some of the most common types.

Major depression

A person with major depression experiences a constant state of sadness. They may lose interest in activities that they used to enjoy.

Treatment usually involves medication and psychotherapy.

Persistent depressive disorder

Also known as dysthymia, persistent depressive disorder causes symptoms that last for at least 2 years. A person with this disorder may have episodes of major depression as well as milder symptoms.

Bipolar disorder

Depression is a common symptom of bipolar disorder, and research shows that people with this disorder may have symptoms around half of the time. This can make bipolar disorder hard to distinguish from depression.

Psychotic depression

Some people experience psychosis with depression. Psychosis can involve delusions, such as false beliefs and a detachment from reality. It can also involve hallucinations — sensing things that do not exist.

Postpartum depression

After giving birth, many women experience what some people call the “baby blues.” When hormone levels readjust after childbirth, changes in mood can result. Postpartum depression, or postnatal depression, is more severe.

There is no single cause for this type of depression, and it can persist for months or years. Anyone who experiences ongoing depression after delivery should seek medical attention.

Major depressive disorder with seasonal pattern

Previously called seasonal affective disorder, or SAD, this type of depression is related to the reduction in daylight during the fall and winter. It lifts during the rest of the year and in response to light therapy. People who live in countries with long or severe winters seem to be affected more by this condition.

Physical symptoms- The physical symptoms of depression include:

• moving or speaking more slowly than usual
• changes in appetite or weight (usually decreased, but sometimes increased)
• constipation
• unexplained aches and pains
• lack of energy
• low sex drive (loss of libido)
• changes to your menstrual cycle
• disturbed sleep – for example, finding it difficult to fall asleep at night or waking up very early in the morning

Social symptoms- The social symptoms of depression include:

• avoiding contact with friends and taking part in fewer social activities
• neglecting your hobbies and interests
• having difficulties in your home, work, or family life

Severities of depression- Depression can often come on gradually, so it can be difficult to notice something is wrong. Many people try to cope with their symptoms without realizing they’re unwell. It can sometimes take a friend or family member to suggest something is wrong.

Doctors describe depression by how serious it is:

• mild depression – has some impact on your daily life
• moderate depression – has a significant impact on your daily life
• severe depression – makes it almost impossible to get through daily life; a few people with severe depression may have psychotic symptoms

Grief and depression- It can be difficult to distinguish between grief and depression. They share many of the same characteristics, but there are important differences between them.

Grief is an entirely natural response to a loss, while depression is an illness.

People who are grieving find their feelings of sadness and loss come and go, but they’re still able to enjoy things and look forward to the future.

In contrast, people who are depressed constantly feel sad. They find it difficult to enjoy anything or be positive about the future. 

Diagnosis

If a person suspects that they have symptoms of depression, they should seek professional help from a doctor or mental health specialist. A qualified health professional can rule out various causes, ensure an accurate diagnosis, and provide safe and effective treatment.

They will ask questions about symptoms, such as how long they have been present. A doctor may also conduct an examination to check for physical causes and order a blood test to rule out other health conditions.

What is the difference between situational and clinical depression? Find out here. 

Tests

Mental health professionals often ask people to complete questionnaires to help assess the severity of their depression.

The Hamilton Depression Rating Scale, for example, has 21 questions. The scores indicate the severity of depression among people who already have a diagnosis.

The Beck Depression Inventory is another questionnaire that helps mental health professionals measure a person’s symptoms.

Is it curable?

While there is no cure for depression, there are effective treatments that help with recovery. The earlier treatment starts, the more successful it may be.

Many people with depression recover after following a treatment plan. Even with effective treatment, however, a relapse may occur.

To prevent relapse, people who take medication for depression should continue with treatment — even after symptoms improve or go away — for as long as their doctor advises.

Find some tips to help prevent depression from returning.

Triggers

Triggers are emotional, psychological, or physical events or circumstances that can cause depression symptoms to appear or return.

These are some of the most common triggers:

• Stressful life events, such as loss, family conflicts, and changes in relationships.
• Incomplete recovery after having stopped treatment too soon
• Medical conditions, such as obesity, heart disease, and diabetes.

Risk factors

Some people have a higher risk of depression than others.

Risk factors include:

• experiencing certain life events, such as bereavement, work issues, changes in relationships, financial problems, and medical concerns
• experiencing acute stress
• having a lack of successful coping strategies
• having a close relative with depression
• using some prescription drugs, such as corticosteroids, some beta-blockers, and interferon
• using recreational drugs, such as alcohol or amphetamines
• having sustained a head injury
• having had a previous episode of major depression
• having a chronic condition, such as diabetes, chronic obstructive pulmonary disease (COPD), or cardiovascular disease
• living with persistent pain

 There’s no single cause of depression. It can occur for a variety of reasons and it has many different triggers.

For some people, an upsetting or stressful life event, such as bereavement, divorce, illness, redundancy, and job or money worries, can be the cause.

Different causes can often combine to trigger depression. For example, you may feel low after being ill and then experience a traumatic event, such as a bereavement, which brings on depression.

People often talk about a “downward spiral” of events that leads to depression. For example, if your relationship with your partner breaks down, you’re likely to feel low, you may stop seeing friends and family and you may start drinking more. All of this can make you feel worse and trigger depression.

Some studies have also suggested that you’re more likely to get depression as you get older and that it’s more common in people who live in difficult social and economic circumstances.

Stressful events- Most people take time to come to terms with stressful events, such as bereavement or a relationship breakdown. When these stressful events occur, your risk of becoming depressed is increased if you stop seeing your friends and family and try to deal with your problems on your own.

Personality- You may be more vulnerable to depression if you have certain personality traits, such as low self-esteem or being overly self-critical. This may be because of the genes you’ve inherited from your parents, your early life experiences, or both.

Family history- If someone in your family has had depression in the past, such as a parent or sister or brother, it’s more likely that you’ll also develop it.

Giving birth- Some women are particularly vulnerable to depression after pregnancy. The hormonal and physical changes, as well as the added responsibility of a new life, can lead to postnatal depression.

Loneliness- Feelings of loneliness, caused by things such as becoming cut off from your family and friends can increase your risk of depression.

Alcohol and drugs- When life is getting them down, some people try to cope by drinking too much alcohol or taking drugs. This can result in a spiral of depression. Cannabis can help you relax, but there’s evidence that it can also bring on depression, particularly in teenagers.

“Drowning your sorrows” with a drink is also not recommended. Alcohol affects the chemistry of the brain, which increases the risk of depression.

Illness- You may have a higher risk of depression if you have a longstanding or life-threatening illness, such as coronary heart disease or cancer. Head injuries are also an often under-recognized cause of depression. A severe head injury can trigger mood swings and emotional problems.

Some people may have an underactive thyroid (hypothyroidism) resulting from problems with their immune system. In rarer cases, a minor head injury can damage the pituitary gland, which is a pea-sized gland at the base of your brain that produces thyroid-stimulating hormones.

This can cause a number of symptoms, such as extreme tiredness and a lack of interest in sex (loss of libido), which can, in turn, lead to depression.