What is depression?
Depression (also called major depressive disorder) is a serious condition that causes persistent feelings of sadness, fatigue, and loss of interest in activities that were once enjoyed. This mood disorder may lead to behavioral, emotional, and physical challenges that can interfere with most areas of a person’s life, including relationships, work, school, social life, and physical health. In some cases, severe depressive symptoms can seriously endanger a person’s life through substance abuse, self-harm, and suicidal feelings or attempts.
Fortunately, with the right treatment, millions of Americans who suffer from depression are able to return to a healthy, fulfilling quality of life. If you think that you or someone you love may be suffering from depression, it’s important to get help right away—no one should have to suffer under the burden of this devastating illness.
What isn’t depression?
Although depression is one of the most common health conditions in the world, it is also one of the most misunderstood. Many people—including some people who themselves suffer from depression—mistakenly believe that those with depression are lazy, weak, or “just feeling down.” They may think that people with depression need to “just get over it,” or that the disease can be cured with positive thinking, exercise, or meditation. Others may deny that depression exists at all.
In reality, depression is a real illness that causes observable behavior changes and may discernibly affect the structure and chemistry of a person’s brain. Like many mental disorders, depression may seem “invisible,” but it is a medical condition that requires clinical diagnosis and treatment.
What are the signs and symptoms of depression?
Every person experiences depression differently, and no two people will have exactly the same symptoms. However, there are a number of common signs and symptoms among people who suffer from depression:
- Feelings of sadness or hopelessness
- Feelings of numbness or emptiness
- Feelings of guilt, self-blame, worthlessness, or low self-esteem
- Loss of interest in hobbies and activities
- Difficulty concentrating, forgetfulness, and/or indecisiveness
- Sleep changes, such as insomnia or oversleeping
- Appetite or weight changes
- Self-harming behaviors
- Fixation on death or suicide, or actual suicide attempts
- Physical problems (such as headaches or digestive issues) that appear without a clear cause
While every person’s experience of depression is unique, psychologists have determined that certain groups of people may show similar patterns of depression symptoms. To accurately identify and diagnose depression across diverse groups, is important to understand the different ways that people may experience and cope with depression.
- Show signs of anger, irritability, or aggression
- Experience sleep changes and fatigue
- Engage in substance abuse
- Die by suicide
- Seek medical help for their physical symptoms rather than their emotional symptoms
- Show signs of sadness, guilt, and worthlessness
- Experience co-occurring mental disorders, particularly anxiety or eating disorders
- Attempt suicide
- Talk about their feelings and symptoms with friends and loved ones
- Seek medical help for their symptoms
- Show signs of fatigue, irritability, or grumpiness
- Show less obvious symptoms of depression
- Experience symptoms of depression that are obscured by the normal aging process or by side effects of medications (such as grief, fatigue, or sleep changes)
- Avoid talking about their symptoms
- Die as a result of their co-occurring illnesses and disabilities
How is depression diagnosed?
According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), a comprehensive guide that mental health professionals use to understand and diagnose mental health conditions, a person can be diagnosed with major depressive disorder if:
- They experience at least five of the common signs of symptoms of depression for at least two weeks. At least one of these symptoms must be depressed mood or loss of interest or pleasure.
- They experience distress or impairment because of their symptoms.
- Their symptoms cannot be attributed to another medical condition.
- Their symptoms are not better explained by another mental disorder, such as schizophrenia.
- They have never experienced a manic episode, which can be a symptom of other mental disorders.
You may be familiar with an assessment called the Patient Health Questionnaire (PHQ-9), a brief, nine-item survey that clinicians often use to identify individuals who may be at risk for major depressive disorder. The PHQ-9 is usually administered in school clinics, doctors’ offices, and other health care settings to quickly screen for depression among large, diverse groups of people. Those who score “high risk” are referred to additional health services and supports for managing depression.
How many people have depression?
Depression is one of the most common conditions in the world. Globally, the condition impacts more than 264 million people each year, more than 800,000 of whom die by suicide as a result of their depression.
- 3 million adults (about 7.1% of the adult population) experienced a major depressive episode.
- More than 1 in 8 young adults (aged 18 to 25) experienced a major depressive episode.
- 2 million adolescents (aged 12 to 17) had at least one major depressive episode, representing 13.3% of the adolescent population.
- Nearly two-thirds of adults and three-quarters of adolescents who experienced a depressive episode had severe impairment as a result of their illness.
Who’s at risk for depression?
Any person can develop depression at any point in their lifetime. However, certain groups of people are more likely to develop depression than others.
- Women are at much higher risk for developing depression than men. In the last year, 8.3% of adult women and 20% of adolescent girls experienced a depressive episode compared to 5.3% of adult men and 6.8% of adolescent boys.
- Young adults aged 18 to 25 are at the highest risk for developing depression.
- People who report two races are more likely to have experienced a depressive episode in the last year.
- Genetics play a role. People with a first-degree relative (such as a parent or sibling) who has depression are two to three times more likely to develop depression.
- People who have experienced trauma, stress, loss, or major life changes are at higher risk for developing depression.
- Depression may be a side effect of some common medications. People who take certain acne medications, high blood pressure drugs, or oral contraceptives may be at higher risk for depression.
- About half of all people who experience a traumatic brain injury (TBI) will develop depression in the year following injury.
How does depression affect a person’s life?
Depression burdens every aspect of life. Physical symptoms of depression (such as headache, sleep changes, chronic pain, and appetite changes) can cause debilitating health problems that may interfere with daily functioning and may require treatment with additional medications, which may cause unwanted additional side effects. Cognitive symptoms of depression (such as difficulty concentrating, forgetfulness, and indecisiveness) can limit a person’s performance and productivity at school or at work.
Meanwhile, emotional and behavioral symptoms of depression (such as sadness, loss of pleasure or interest, and hopelessness) usually takes a toll on a person’s ability to maintain healthy social and family relationships. A person with depression may become isolated and withdrawn, preferring to spend time alone rather than engage in activities with loved ones that once brought them joy and fulfillment. Furthermore, a person with depression may be aware that their illness has reduced their own quality of life or impacted their loved ones’ lives, but they may feel powerless to change or recover. This internal conflict can compound a depressed person’s feelings of guilt and hopelessness, which may in turn exacerbate the depressive episode.
In severe cases, depression may become life-threatening. A person with depression may physically harm themselves, self-medicate with alcohol or other substances, or think about or attempt suicide. Rapid, intensive treatment is often necessary to protect the personal safety of individuals with severe depression.
What’s happening in the brain?
To treat mental disorders like depression, neuroscientists need to understand the underlying brain processes that cause the illness. They believe that depression is caused by malfunctioning brain cells in the prefrontal cortex, an area of the brain that is responsible for regulating behavior, emotions, and cognition. Brain cells (called neurons) work by transmitting small electrical pulses to one another, signaling them to release chemicals called neurotransmitters. These neurotransmitters help the brain perform various important functions, and a proper balance of three particular neurotransmitters—called dopamine, serotonin, and norepinephrine—is necessary to maintain emotional health and wellbeing. When neurons in the prefrontal cortex malfunction, they may fail to send the correct electrical signals to stimulate a balanced release of these neurotransmitters. The subsequent chemical imbalance of serotonin, dopamine, and norepinephrine may be responsible for depression.
How is depression treated?
Fortunately, most causes of depression will improve with treatment—especially when treatment is initiated early in a depressive episode. The most common treatments are psychotherapy and antidepressant medications, or usually (in 65% of cases) a combination of the two. However, an estimated 10-30% of people with depression are treatment-resistant, meaning that their depression does not successfully respond to typical treatments. For people with treatment-resistant depression, innovative non-traditional treatment options may offer renewed hope.
- Therapy: Psychotherapy is an effective treatment for many people with depression. Most psychiatrists who prescribe antidepressant medications also recommend that their patients attend regular therapy sessions to discuss their feelings, symptoms, and overall health with a trained mental health professional. Licensed therapists use evidence-based approaches like cognitive behavioral therapy (CBT) to help their patients identify harmful patterns of thinking, develop healthy coping mechanisms, improve communication skills, and reduce stress.
- Medications: Traditional antidepressant medications like selective serotonin reuptake inhibitors (SSRIs) and selective norepinephrine reuptake inhibitors (SNRIs) can help the brain release a healthy balance of the neurotransmitters involved in depression. Most people who take antidepressant medications see an improvement in their symptoms within a few weeks, but some people may need faster-acting, higher-intensity treatment options to recover from depression.
Options for treatment-resistant depression
Neuroscientists are working diligently to develop new approaches to alleviate the burden of depression among people with treatment-resistant illness.
- Esketamine: In recent years, they have determined that a drug called esketamine (a more potent form of ketamine) may relieve symptoms of depression. Importantly, while traditional antidepressants may take weeks to become effective, esketamine may improve depressive symptoms within hours, offering rapid relief to people with severe, life-threatening depression who are at immediate risk for self-harm or suicide. In 2019, the Food and Drug Administration (FDA) approved an esketamine nasal spray for treatment-resistant depression. Unlike traditional antidepressant medications, esketamine must be administered with supervision from a health care provider because the drug is known to cause sedation, cognitive impairment, and addiction. These side effects can be serious, but esketamine may be a necessary, life-saving option for many people with severe, treatment-resistant depression.
- Brain stimulation: Another cutting-edge option is transcranial magnetic stimulation (TMS), an FDA-approved, non-invasive, non-pharmacological therapy for people with treatment-resistant depression. During a TMS session, a patient receives small, painless bursts of magnetic energy that stimulate electrical currents in certain areas of the brain, helping neurons to release a healthy balance of neurotransmitters. Most TMS sessions last for about an hour, and most people receive five sessions per week for four to six weeks. Evidence suggests that as many as 70% of people with treatment-resistant depression will experience significant improvement in their symptoms, while as many as 40% will experience full remission. Most people who undergo TMS maintain their improvements for at least three months after completing the full treatment course. A small number of people may experience a relapse, but more than 3 in 4 of these patients regain their progress with subsequent TMS treatments. As a result, neuroscientists consider TMS to be a remarkably successful, long-term treatment option for individuals with treatment-resistant depression.
How can I get help for depression?
Most people experiencing depression can return to normal life with professional support, but an estimated 35% of adults and 60% of adolescents with depression never receive treatment for their illness. Prolonged untreated depression tends to become more severe over time and is associated with negative health outcomes and reduced quality of life. Consequently, it is very important to remain watchful for early signs of depression to ensure that you or your loved ones receive immediate support during a depressive episode.
If you think that you or a loved one may be suffering from depression, talk to a health care provider or mental health professional as soon as possible. If you or someone you know is experiencing a mental health crisis, call 911 or call the toll-free, 24/7 National Suicide Prevention Lifeline at 1-800-273-TALK.