Understanding Major Depressive Disorder: Causes, Symptoms, And Treatments

Medically reviewed by Melissa Guarnaccia, LCSW
Updated May 22, 2023by BetterHelp Editorial Team

For many people, a diagnosis of major depressive disorder (clinical depression) can feel overwhelming and isolating. However, research shows that people with depression are not alone: the World Health Organization recognizes depression as the leading cause of disability worldwide, and it’s a major contributor to the global burden of disease.

In a given year, major depressive disorder affects roughly about 7.1% of Americans aged 18 and older—which translates to 17.3 million people.  Depressive disorders don’t discriminate—they affect people of all genders, ages, races, and economic backgrounds. The risk factors of depression or major depressive disorder can include genetic and environmental factors, such as a family history of depression or stressful life events.

Although major depressive disorder can significantly affect several areas of life, effective treatment is available for mild, moderate, and even severe cases. If you or a loved one is experiencing this mental health condition, remember that its symptoms are recognizable and treatable. Read on for critical information about the causes, symptoms, and treatments for major depressive disorder.

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What Is Major Depressive Disorder?

While most of us experience sadness on occasion, major depressive disorder is associated with intense feelings of sadness and low mood or energy.

As defined by the American Psychological Association (APA),major depressive disorder is characterized by persistent sadness and other symptoms of a major depressive episode. These episodes often involve more severe sadness, pessimism, and other negative emotions that can interfere with daily functioning. 

If you’ve been diagnosed with major depressive disorder, your doctor might have referenced the symptom anhedonia to help you understand your condition. This term describes the inability to enjoy experiences or activities you’d normally find pleasurable: a primary symptom of clinical depression and depressive episodes. 

According to the National Institute of Mental Health, major depressive disorder is one of two common forms of depression. The other type of depression, persistent depressive disorder (dysthymia), is less severe than major depression but lasts longer, usually for at least two years.

What Are The Symptoms Of Major Depressive Disorder?

In addition to persistent sadness and depressive episodes, people with major depressive disorder often show other symptoms, including: 

  • Bodily symptoms including physical pain, weakness, fatigue, and low energy
  • Depressive episodes that last most of the day, nearly every day, for at least two weeks
  • Poor concentration
  • Excessive guilt or low self-worth
  • Hopelessness
  • Thoughts about dying or suicide
  • Changes in appetite or weight
  • Disrupted sleep

Because depression can range from mild to severe, a person may not experience some of these symptoms or may experience milder versions. It is important to remember that everyone experiences major depressive disorder symptoms differently, and they may look different for each person.

A mental health professional may inquire about your depressive symptoms, including any suicidal thoughts, weight gain or weight loss, chronic pain, or changes in behavior, to diagnose depression or another mood disorder. This can provide insight into the severity and nature of your medical condition or mental illness and may help in the formation of a treatment plan. It is important, to be honest in your response, so that they can provide an accurate diagnosis. 

If you are thinking about suicide, considering harming yourself or others, feeling that any other person may be in any danger, or if you have any medical emergency, you must immediately call the emergency service number (1-800-273-8255 in the US and 0800-689-5652 in the UK) and notify the relevant authorities. Seek immediate in-person assistance.

The American Psychiatric Association has laid out specific diagnostic criteria to identify major depressive disorder. To meet the criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnostic criteria, a person must have at least five of the primary symptoms, which persist daily for at least two weeks. In some cases, people may experience a single depressive episode, in which case they may not be diagnosed with major depressive disorder. A major depressive episode may also be a symptom of bipolar disorder.

Causes Of Major Depressive Disorder

Although the cause of major depressive disorder isn’t always clear, psychologists believe the condition is traceable to a combination of factors. Your depression risk may be higher if you have a family history of depression, or have experienced traumatic or stressful events in your life. You may lower your risk to prevent depression by getting regular exercise, eating a healthy diet, and getting enough sleep. Hormonal and seasonal changes could give rise to depressive episodes, particularly in the case of perinatal and postpartum depression and seasonal affective disorder.

In addition to these cyclical changes, which can be traced to changes in the seasons or our bodies, the following factors can increase the risk of developing clinical depression: 

  • Genetics: People whose relatives have clinical depression may be more likely to become depressed.
  • Stressful life events: Upsetting or traumatic events, such as the loss of a loved one or work-related pressure, can catalyze or worsen depression.
  • Brain chemistry: Chemical imbalances in the brain, as well as faulty mood control, can contribute to depression, according to the Harvard Medical School.
  • Other medical conditions: Diabetes, cancer, Parkinson’s disease, thyroid disorders, and other physical illness diagnoses can increase your risk of developing depression.
  • Psychiatric comorbidities: People with other mental health disorders, such as eating disorders, post-traumatic stress disorder (PTSD), or panic disorder, are also more likely to have depression
  • Medications: Some prescription medications, as well as recreational drugs and alcohol, have depressive side effects.
  • Personality: Some people are simply predisposed to develop depression, particularly if they’re easily overwhelmed and lack healthy coping strategies for stress management.

Despite the effects of depression, with social support, self-care, and an understanding of your treatment options, you can live a rewarding, meaningful life after a diagnosis of major depressive disorder. 

Ready To Seek Treatment For Major Depressive Disorder?

Getting Treatment For Clinical Depression

The first step to treating clinical depression is recognizing the symptoms and understanding that with professional support, it’s possible to get better. Initial treatment usually involves talking to your healthcare provider, who will assess your emotional and physical problems and determine if you meet the criteria for clinical depression.

According to the National Institute of Health, up to 80% of people treated for clinical depression show improvement in their symptoms within four to six weeks of beginning medication, psychotherapy, support groups, or a combination of those treatments.

Depending on the severity of your symptoms, your healthcare provider may recommend some (or all) of the following treatments: 

1. Medication

Medical doctors commonly prescribe antidepressants to treat depression. Selective serotonin reuptake inhibitors or SSRIs are one of the most commonly prescribed antidepressants. These medications generally take four to eight weeks to work and reduce common symptoms such as lack of appetite, poor concentration, and sleep disturbances. Oftentimes, medications resolve these symptoms before improving mood, so it can take some time to experience the full benefits of the treatment.

Based on your depressive symptoms and your body’s response to the medication, your doctor may recommend other FDA-approved medications. Consult with your primary care doctor or psychiatrist for more information before integrating any medications into your treatment plan.

2. Brain Stimulation Therapy

This innovative technology involves activating the brain directly with electricity or magnetic waves. Brain stimulation therapy is less common than medications and psychotherapy, but it holds promise for major depressive disorder and other mental health conditions, especially those that are resistant to more traditional treatments.

3. Psychotherapy

In addition to or separate from medication, psychotherapy can be an effective treatment for major depressive disorder. Also called “talk therapy” or simply counseling, psychotherapy teaches patients how to change their thought patterns, behaviors, and habits to overcome the symptoms of depression.

Common forms of therapy include: 

a) Support Groups

Support groups offer a safe place where people can discuss their emotions, unique circumstances, and goals with other people who can empathize with their experience of depression. Many groups also focus on developing healthy coping strategies, connecting with others through storytelling and active listening, and cultivating a sense of hope.

b) Cognitive Behavioral Therapy (CBT) 

CBT is a highly effective form of talk therapy that helps people understand the relationship between their thoughts, feelings, and behaviors. By teaching someone how to alter unhelpful thinking patterns, a therapist can help them develop healthier behaviors and improve their emotional control.

In addition to major depression, CBT is commonly used to treat post-traumatic stress disorder and other mental health conditions.

c) Interpersonal Therapy (IPT)

IPT is a form of talk therapy that focuses on an individual’s current interpersonal problems, goals, and relationships. This is usually a structured and time-limited treatment lasting 12-16 weeks.

Online Therapy For Major Depressive Disorder

In the digital era, CBT, IPT, and other forms of talk therapy are now offered online, increasing the convenience of quality mental health care. Using an online platform like BetterHelp, you can connect with an online therapist at a time and place that works best for your schedule. These licensed therapists are thoroughly vetted and have years of experience supporting clients with clinical depression, anxiety, and related mental health conditions. 

Given the number of people living with depression, many researchers have devoted their careers to studying its treatment. Based on scientific literature, online therapy for depression can be just as effective as in-person therapy. In 2021, for instance, a group of researchers found associations between internet-based CBT (iCBT) and significant improvements in symptoms of anxiety, depression, and psychological distress, based on an iCBT program in Australia with over 6,000 participants.

Online therapy helps people get the help they deserve without the financial burden or hassle of commuting to an office. With BetterHelp, you can connect with a licensed therapist via audio or video chat from the comfort of your home or from anywhere with an internet connection. You can also send your therapist any concerns about depression or anything else via in-app messaging, and they’ll get back to you as soon as they can.


Major depressive disorder is a global condition, but it’s also highly treatable. You don’t need to face this condition alone. With the guidance of a therapist, your primary care doctor, and supportive loved ones, you can create a path toward recovery that works best for you. With BetterHelp, you can be matched with a therapist with experience treating people living with depression. Together, you can craft a personalized plan that accounts for your symptoms, lifestyle, and mental health goals. Take the first step to treating your depression and reach out to BetterHelp today.

You Don’t Have To Face Depression Alone. Our Experienced Counselors Can Help.

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