What Is Depression? Symptoms & Causes

Depression is a mental health problem that is more than just feeling sad or down. It is a condition that can have an enormous impact on a person’s life and health. Depression can affect anyone, no matter how old they are, what race they are, or how much money they have. Depression affects about 5% of people around the world.1 Roughly 8.4% of the U.S. population, or 21 million Americans, have experienced severe depression at some point in their lives.2

Depression can cause many physical and mental signs, such as tiredness, sleeplessness, changes in appetite, and a constant feeling of despair (complete or almost complete loss of hope, usually accompanied by desperation, anguish, and sadness) or worthlessness.1 To get the right help and care for depression, it’s important to know the signs and symptoms. In this article, we will talk about the different types of depression, how to tell if someone has it, what can cause it, and how to treat it.

Signs and Symptoms of Depression

Depression can show up in many ways, such as physical feelings, emotional changes, and behaviors. No two people experience depression in the same way, but there are some common signs to keep in mind. These signs can include changes in mood, such as feeling persistently sad, hopeless, or empty. You might also notice physical changes, like feeling more tired than usual or having trouble sleeping. Behavioral changes can include avoiding activities you once enjoyed or withdrawing from social situations. Understanding these symptoms can help you identify depression and get the support you need to feel better.

Emotional Symptoms and Signs of Depression

If you have depression, you might feel really sad or hopeless all the time. You might lose interest in things you used to enjoy, like hobbies or hanging out with friends. It can be hard to make decisions or focus on things because your mind feels foggy. You might also feel frustrated or irritable, and it’s common to have thoughts of worthlessness or excessive guilt.3 Sometimes, depression can even make you think about hurting yourself or not wanting to live anymore. These are all serious symptoms that shouldn’t be ignored, and it’s important to seek help if you’re experiencing any of them.

Physical Symptoms and Signs of Depression

Depression can affect not just your mind but also your body. It can cause physical changes that may impact your daily life.4

Changes in Appetite: One of the most common physical symptoms of depression is changes in appetite. You may find yourself overeating, or you might not feel like eating at all. These changes can lead to weight gain or weight loss, respectively, which can further impact your mood and self-esteem.

Sleep Disturbances: Depression can also disrupt your sleep patterns. You may find yourself sleeping too much or having trouble sleeping and waking up feeling tired. This can make it difficult to focus during the day and can affect your energy levels.

Low Energy: Depression can make you feel tired and sluggish, making it hard to get things done or take part in activities you enjoy.

Body Pains: Physical discomforts, such as headaches, stomachaches, or muscle tension, can be a sign of depression. These symptoms may not have an obvious cause, but they can contribute to feelings of discomfort and frustration.

Restlessness or Agitation: Some people with depression may experience restlessness, agitation, or an inability to sit still. This can be a sign of anxiety or tension.

Slow Movements or Speech: Others may experience slowed movements, speech, or thinking. This can make it challenging to carry out daily activities and interact with others.

Sexual Problems: Depression can impact your sex drive and cause sexual problems, such as a lack of interest or difficulty with arousal or orgasm.

Behavioral Symptoms and Signs of Depression

Depression not only manifests itself emotionally and physically, but it can also alter how you behave. Some indications and symptoms of depression in terms of behavior are as follows5:

Social Withdrawal: Depression can make you avoid social situations and pull away from your friends and family. You might not feel like interacting with others because you lack the energy or desire to do so or because you’re afraid of being an inconvenience to those around you.

Loss of Interest: You might find that you no longer like doing the things you used to enjoy. You may no longer enjoy your hobbies, sports, or other relaxation activities, or you may no longer see the point in doing them.

Difficulty Concentrating: Depression can make it hard to pay attention, remember details, or decide what to do. You might find that you forget things or have trouble getting things done.

Procrastination: You may put off tasks that must be completed, regardless of how urgent or essential they are. Your emotional and work relationships could be negatively affected by this.

Neglecting Responsibilities: Depression can make it hard to keep up with your responsibilities, like work, school, or home chores. You might find that you are often late or missing or that you can’t do things as well as you usually do.

Drugs or Alcohol Abuse: Some depressed people use drugs or alcohol to help them deal with their emotions. Abuse of drugs or alcohol can worsen depression as well as cause other issues like addiction.

Suicidal Thoughts or Actions: If your depression is serious, you may have suicidal or self-harming impulses. You should get help right away if you’re having these thoughts.

Types of Depression

Depression may appear in different forms, and it’s important to know what those forms are so you can spot the signs and get the right help. These are some of the most common types of depression:6

Major Depression

Also known as clinical depression, major depression is characterized by a persistent feeling of sadness, hopelessness, or emptiness that lasts for at least 2 weeks. This kind of depression can affect every part of your life and can even cause physical symptoms.

Persistent Depressive Disorder

Persistent depressive disorder is a type of depression that is also known as dysthymia, and is a milder but longer-lasting form of depression. Symptoms can last for at least two years and can interfere with daily life.

Seasonal Affective Disorder

Seasonal affective disorder is a type of depression linked to changes in the seasons. It is most common in the fall and winter months. It can cause symptoms such as fatigue, overeating, and difficulty sleeping.

Bipolar Disorder

Bipolar disorder is a condition that involves cycles of extreme highs (mania) and lows (depression). People with bipolar disorder may have symptoms of both depression and mania, which can cause significant disruptions in their lives.

Postpartum Depression

Postpartum depression is a specific type of depression that can develop after childbirth and is believed to be related to changes in hormones and other factors. Some common symptoms of postpartum depression include feelings of anxiety, sadness, and difficulty bonding with the baby.

Psychotic Depression

Psychotic depression is a type of depression that can involve symptoms of psychosis, such as delusions or hallucinations. It is a severe form of depression that can require hospitalization.

Causes of Depression

The causes of depression are complex and can be different from one person to another. There is no single cause of depression, but rather a combination of genetic, environmental, and psychological factors that can contribute to the development of this condition.7 Here are some of the most common causes of depression:

  • Genetics: Research has shown that genetics may play a role in depression, which means that if you have a family history of depression, you may be more likely to develop the condition.
  • Brain chemistry: Chemical imbalances in the brain can contribute to the development of depression. Neurotransmitters, which are chemicals in the brain that control mood, can be imbalanced in individuals with depression.
  • Trauma and stress: Traumatic events, such as the death of a loved one or a difficult life event, can trigger depression. Chronic stress, such as ongoing financial or relationship problems, can also contribute to the development of depression.
  • Medical conditions: Certain medical conditions, such as chronic pain, cancer, or thyroid problems, can contribute to the development of depression.
  • Substance abuse: Substance abuse, such as drug or alcohol abuse, can lead to changes in brain chemistry that can contribute to the development of depression.
  • Medications: Certain medications, such as some types of blood pressure medications or hormonal contraceptives, can contribute to the development of depression as a side effect.

Complications of Depression

Depression can have a significant impact on a person’s life and can lead to a variety of complications. Here are some of the most common complications of depression8:

Substance Abuse

Individuals with depression may start using drugs or alcohol as a way to cope with their symptoms. This can lead to substance abuse, which can make depression worse and increase the risk of developing other health problems.

Social Isolation

Depression can make it difficult for people to connect with others and may lead to feelings of loneliness and social isolation. This can worsen depression and make it harder to recover.

Relationship Problems

Depression can put a strain on relationships, as people with depression may have difficulty communicating with their loved ones and may withdraw from social activities.

Work or School Problems

Depression can affect a person’s ability to concentrate and may lead to missing work/school or poor performance.

Physical Health Problems

Depression has been linked to a variety of physical health problems, such as chronic pain, heart disease, and obesity.


Depression is a leading cause of suicide, and individuals with depression may be at an increased risk of suicidal thoughts or behavior.

Risk Factors for Depression

Depression is a complex condition that can be caused by a variety of factors. While anyone can experience depression, there are certain risk factors that can increase the likelihood of developing the condition. Here are some of the most common risk factors for depression9:

  • Gender: Women are more likely than men to develop depression, although the reasons for this are not understood.
  • Age: Depression can occur at any age, but it is more common in middle-aged and older adults.
  • Personal history: If you have experienced depression in the past, you may be at higher risk of developing the condition again.
  • Medical conditions: Certain medical conditions, such as chronic pain, cancer, or heart disease, can increase the risk of developing depression.
  • Substance abuse: Substance abuse can increase the risk of depression, and depression can increase the risk of substance abuse.
  • Genetics: Depression can run in families, suggesting genetics play a role in depression. If you have a family history of depression, you may be at a higher risk of developing the condition.
  • Brain chemistry: Depression has been linked to an imbalance in certain chemicals in the brain, such as serotonin and dopamine.
  • Life events: Traumatic or stressful life events, such as the death of a loved one, a divorce, or a job loss, can trigger depression.

Diagnosis and Testing for Depression

If you are experiencing symptoms of depression, it is important to talk to your healthcare provider. Your provider may ask you questions about your symptoms, medical history, and any medications you are taking. They may also perform a physical exam to rule out any other medical conditions that could be causing your symptoms.

In addition to a physical exam, your provider may conduct a mental health evaluation, which may involve a series of questions and assessments to evaluate your mood, behavior, and thought patterns. Though there is no single test that can diagnose depression, they may also ask you to complete a questionnaire, such as the Patient Health Questionnaire-9 (PHQ-9), to assess the severity of your depression.10

It is important to note that depression can be difficult to diagnose because it shares symptoms with other mental health disorders and medical conditions. Some providers may order blood tests or other laboratory tests to rule out any other medical conditions that could be contributing to your symptoms. Your provider may refer you to a mental health specialist, such as a psychiatrist or psychologist, for further testing.

It is also important to note that seeking a diagnosis and treatment for depression can be a positive step toward improving your mental health and overall well-being. If you are experiencing symptoms of depression, it is important to speak with a healthcare provider to determine the best course of action for your individual needs.

In conclusion, depression is a common mental health disorder that can have a significant impact on a person’s life. Recognizing the symptoms, causes, and different types of depression is crucial to getting the right treatment and support. While depression cannot be cured, it can be effectively managed with medication, therapy, or a combination of both. The first step in managing depression and improving your quality of life is seeking help from a mental health professional.

Frequent Asked Questions About Depression

Q: What is the difference between depression and feeling sad?

A: Feeling sad is a normal human emotion that typically arises in response to a specific event, such as the loss of a loved one or a difficult situation. Depression, on the other hand, involves persistent feelings of sadness and hopelessness that can last for weeks or months, even in the absence of an identifiable cause.

Q: Is depression a lifelong condition?

A: Depression can be a chronic (long-lasting) condition for some individuals, but it can also be effectively treated with the right approach, allowing individuals to experience periods of remission and improved quality of life.

Q: Can depression be inherited?

A: There is evidence to suggest that depression can have a genetic component, meaning that it can be passed down through generations. However, it is also influenced by environmental factors and life experiences.

Q: What causes depression?

A: Depression can be caused by a variety of factors, including genetics, brain chemistry, life events, and other medical conditions. Read more about causes of depression and risk factors for depression.

Q: Can children and teenagers experience depression?

A: Yes, depression can affect people of all ages, including children and teenagers.

Q: How can I support someone who is struggling with depression?

A: Supporting someone with depression can involve listening without judgment, offering encouragement and reassurance, and helping them seek professional help if needed. See our resources for living with depression for more information about supporting a loved one with depression.

Q: Can depression be prevented?

A: While there is no surefire way to prevent depression, engaging in healthy lifestyle habits such as regular exercise, getting enough sleep, and managing stress can help reduce the risk of developing depression.

Q: Is depression a sign of weakness?

A: No, depression is not a sign of weakness. It is a medical condition that can affect anyone, regardless of their strength or resilience.

Resources for Living with Depression

Explore the websites listed below to discover resources in your vicinity or to learn more about mental health.

  • The National Alliance on Mental Illness (NAMI) is an organization focused on enhancing the quality of life of Americans who are impacted by mental illness. Its primary goal is to help with developing improved living conditions for these individuals.
  • National Suicide Prevention Lifeline: If you find yourself in a state of emotional distress or contemplating suicide, you can access the National Suicide Prevention Lifeline. It is a free-of-charge and confidential hotline that operates around the clock to provide suicide prevention help to anyone in need.
  • Postpartum Support International: The goal of this organization is to raise consciousness among both the general population and professional communities regarding the emotional alterations that women undergo during pregnancy and in the postpartum period.
  • Depression in Women: The National Institute of Mental Health provides a comprehensive resource for learning about depression in women, including information on its causes, symptoms, and available treatments.