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Depression (Major Depressive Disorder)

Depression is a prevalent mental health problem characterized by a constant sense of sadness and alterations in your thoughts, sleeping patterns, eating habits, and actions. There are various types of depression, and treatment typically involves medication, psychotherapy, or a combination of both. Generally, it's important to seek medical assistance as early as possible.

By Able Health I Medically reviewed by Dr. Alireza Estedlal

Page last reviewed: February 2024 I Next review due: February 2026

What is depression?

Depression is defined as a mood condition causing an unending feeling of sadness and lack of interest in activities or things you initially liked. This disorder could also lead to problems with a person's thinking, eating, sleeping, or memory.

Feeling sad about something or grieving over challenging situations in life like job loss or divorce is usually normal. However, it's different with depression, such that it persists almost daily for at least 2 weeks and is accompanied by additional symptoms besides sadness.

There are different kinds of depressive disorders. Major depressive disorder, also known as clinical depression, is usually simply referred to as 'depression' and is the most serious type of all.

If not treated, depression could worsen and endure for a longer period. In more severe situations, it may result in self-harm or suicide. Fortunately, treatments are highly effective in managing symptoms.

What are the types of depression?

The American Psychiatric Association's Diagnostic Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) categorizes depression as follows:

  • Clinical depression (major depressive disorder): The diagnosis of this disorder shows that a person has been feeling sad, worthless, and low on most days for 2 weeks. This is accompanied by other symptoms like sleeping problems, interest loss in certain activities, or appetite changes. Major depressive disorder is the most common, and severe type of depression.
  • Persistent depressive disorder (PDD): This is a mild depressive disorder that endures for at least 2 years with symptoms that are normally less serious compared to clinical depression. Previously, medical practitioners referred to this condition as dysthymia.
  • Disruptive mood dysregulation disorder (DMDD): This disorder results in long-lasting, intense irritation as well as recurrent rage outbursts in minors. The symptoms often start atten years old.
  • Premenstrual dysphoric disorder (PMDD): This disorder involves symptoms of premenstrual syndrome (PMS) in addition to mood symptoms, including depression, anxiety, or intense irritability. While the signs usually improve after a few days when the period starts, they may be serious enough to disrupt one's life.
  • Depressive disorder due to another health condition: Several health problems, such as heart disease, Parkinson's disease, cancer and hypothyroidism, can cause body changes that lead to depression. Therefore, addressing the underlying medical condition significantly improves depression symptoms.

In addition, there are specific types of major depressive disorder such as:

  • Seasonal affective disorder (seasonal depression): This usually occurs during winter and fall and resolves in summer and spring seasons.
  • Prenatal depression and postpartum depression: Normally, prenatal depression arises during pregnancy, while postpartum depression happens after 4 weeks of childbirth. They are classified as 'major depressive disorder with peripartum onset.'
  • Atypical depression: Also referred to as major depressive disorder with atypical features, the symptoms tend to slightly differ from 'typical' depression. Mood activity, which is the temporary improvement of the mood due to positive events, is the major difference. Other common symptoms are increased sensitivity to rejection and appetite.

Also, individuals with bipolar experience depression events along with manic or hypomanic episodes.

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Whom does depression affect?

Depressive disorder can affect both adults and children. However, women and persons assigned female at birth are at a higher risk of having depression compared to men and those assigned male at birth.

Also, certain risk factors raise the likelihood of developing depression. These are the medical conditions associated with increased depressive disorder rates:

  • Neurodegenerative diseases like Alzheimer's disease and Parkinson's disease

  • Multiple sclerosis

  • Stroke

  • Seizure disorders

  • Macular degeneration

  • Cancer

  • Chronic pain

Signs and Symptoms

Depression is characterized by symptoms such as intense sadness, loss of interest, low energy, and changes in sleep or appetite, among others. While major depressive disorder is chronic, it happens in episodes and lasts for a few weeks or months.

What are the symptoms of depression?

Depression symptoms can slightly differ based on the type and severity. But generally, the symptoms may include the following:

  • A sense of hopelessness, sadness, or worry. In kids and adolescents, this may present as irritability instead of sorrow.

  • Increased irritability or frustration.

  • Lack of interest or pleasure in things you used to enjoy.

  • Consuming too little or too much, leading to weight loss or gain.

  • Low energy or tiredness.

  • Insomnia (difficulty sleeping) or hypersomnia (too much sleep).

  • Difficulty remembering things, concentrating or deciding.

  • Having physical problems such as stomachache, headache, or sexual dysfunction.

  • Thoughts of suicide or self-harm.

What Causes Depression?

Medical professionals have yet to determine the actual cause of depressive disorder. However, it is believed that certain factors are likely to contribute to its occurrence. They include:

  • Brain chemistry: A chemical imbalance in some areas of the brain regulating thoughts, mood, appetite, behaviour, and sleep can occur in people with depression.
  • Hormone levels: Alterations in female hormones like oestrogen and progesterone at varying times, such as in the menstrual cycle, postpartum, perimenopause, and menopause, are likely to contribute to depression.
  • Family history: Having a family history of depressive disorder or other mood problems increases the possibility of depression.
  • Early childhood trauma: Certain childhood events can impact how the body responds to fears and stress.
  • Brain structure: A less active frontal lobe in the brain is linked to higher risks of developing depression. Nonetheless, it’s unclear if this occurs before or after depressive symptoms begin.
  • Health conditions: Certain medical problems like chronic disorders, severe pain, insomnia, stroke, Parkinson's disease, cancer and heart attack increase the possibility of depression.
  • Substance abuse: People with a history of alcohol or substance abuse are at a higher risk of depression.
  • Pain: Prolonged chronic emotional or physical pain can significantly increase the likelihood of developing depression.

Risk factors

The risk factors associated with depressive disorder can be medical, genetic, biochemical, social, or circumstantial. The most prevalent depression risk factors are:

  • Gender: Major depression in females is two times more common compared to males.
  • Genes: Having a family history of depressive disorder increases your possibility of developing the condition.
  • Certain drugs: Medications such as some forms of hormonal birth control, beta-blockers, and corticosteroids are likely to increase the likelihood of developing depression.
  • Vitamin D deficiency: Low vitamin D levels have been associated with symptoms of depression.
  • Substance abuse: Nearly 21% of persons with substance abuse disorder experience depressive symptoms.
  • Medical diseases: Chronic medical conditions have been linked to a higher risk of depression. Individuals with heart disease are nearly two times more likely to develop depression, and up to 25% of those with cancer may experience depressive symptoms.

How is Depression Diagnosed?

Depression diagnosis involves a thorough evaluation of the symptoms, medical history, and psychological health history. Depending on the symptoms, medical providers may identify a specific form of depression, likepostpartum depressionor seasonal affective disorder.

To be diagnosed with depression, one must show at least five symptoms of depression nearly every day for at least 2 weeks. Providers may also recommend diagnostic procedures, including blood tests, to rule out underlying health conditions that could be contributing to the depressive symptoms.

How is Depression Treated?

Depressive disorder is one of the highly treatable psychological health problems with about 80 to 90 percent of individuals responding well to treatment.

The common depression treatment options are:

  • Psychotherapy: Also called talk therapy, it involves discussing with your mental health physician to determine and adjust unhealthy thoughts, emotions, and actions. While there are several kinds of psychotherapy, the most prevalent is cognitive behavioural therapy (CBT). Some people only require a brief therapy, whereas others need to continue with the treatment for months or even years.

  • Medication: Antidepressants are prescription drugs that can help alter brain chemistry, causing depression. Many forms of antidepressants are available and it might take a while to find the right one for your condition. Some of these medications have side effects that usually get better over time. However, if they fail to improve, inform your provider so they can recommend different suitable medicines.
  • Complementary medicine: Medical providers can give this treatment alongside traditional Western medication. Individuals with moderate depression or persistent symptoms can enhance their well-being through alternative therapies like acupuncture, hypnosis, biofeedback, or massage.
  • Brain stimulation therapy: This may be beneficial to persons with severe depressive disorder or depression with psychosis. Forms of brain stimulation therapy are transcranial magnetic stimulation (TMS), electroconvulsive therapy (ECT) and vagus nerve stimulation (VNS).

In addition, you can practice the following strategies at home to improve symptoms of depression:

  • Regular physical activity

  • Getting adequate and quality sleep

  • Consuming healthy diet

  • Avoiding consumption of alcohol


Although depression is not always preventable, you can lower the risk by taking these measures:

  • Keeping a healthy sleeping schedule.

  • Stress management with healthy coping strategies.

  • Practicing routine self-care activities like meditation, exercising or yoga.

People with a history of depression have an increased possibility of recurrence. It's thus important to seek immediate assistance if you experience depressive disorder symptoms.

Outlook for Depression

Depression can be either a temporary or a long-term problem. Treatment may not permanently eliminate depression, but it tends to make the symptoms a bit manageable. Effective management typically involves identifying the appropriate combination of medicines and therapies.

Consult your healthcare provider if one treatment is not working. This is because they can assist you in developing a better treatment plan that may be effective in managing your condition.