Causes, Signs & Effects of Depression

People who struggle with depressive disorders find that their illness impacts their mood, body, and mind. Symptoms of depressive disorders can interfere with daily life, impede normal functioning, and cause significant emotional distress.

More About Depression

Learn more about depression

Depressive disorders are more than a simple passing sad mood – they cannot be willed away and people who have depressive disorders can’t just “pull themselves together.” Without proper treatment, people who have these disorders have symptoms that can persist from weeks to years. Depression is a serious mental health disorder, but it is treatable. People who receive effective care can lead much happier and more satisfying lives. There are several major types of depressive disorders that have variable symptomatology, persistence, and severity. These include:

Major depressive disorder is characterized by a combination of intense symptoms that impede a person’s ability to work, eat, sleep, study, and enjoy once-pleasurable activities. For a diagnosis of major depressive disorder, these symptoms and their impact on a person’s life must last for at least two week.

Persistent depressive disorder involves symptoms that are less severe than major depression, but that last for two years or more. This form of depression was previously referred to as dysthymia. People who have persistent disorder will struggle with issues such as sadness, lack of energy, diminished mood, and other issues. They may also experience episodes of major depression.

Many people who have depressive disorders do not seek treatment, however it is a very manageable chronic condition. With proper treatment, even people with very severe cases of depression are able to get better. The proper combination of medications, therapies, and self-care techniques can very effectively help people who have depressive disorders lead a happy and productive life.


Statistics on depression

Each year, depressive disorders affect 5% to 8% of adults in the United States, meaning that approximately 25 million people in the U.S. will have an episode of major depression this year. Unfortunately, only about half of these people will receive treatment.

What Causes Depression?

Learn about the causes and risk factors for depression

Your risk for developing a depressive disorder can be influenced by a variety of genetic, biological, and environmental factors. It should be noted that some cases of depressive disorders occur without a notable trigger or risk factor. The most common causes and risk factors for depression include:

Genetic: Depressive disorders tend to run in families. People who have a first-degree relative who struggles with depressive disorders are more likely to develop depressive disorders than those without a similar family history.

Environmental: Depressive disorders may be triggered by intensely traumatic events, such as natural disasters, the loss of a loved one, or the breakup of a romantic relationship.

Risk Factors:

  • Being female – women are 70% more likely than men to report depressive disorders
  • History of depression as a child or adolescent
  • Drug or alcohol abuse
  • History of borderline personality disorder, anxiety disorders, or PTSD
  • Chronic, severe illnesses

Signs of Depression

Signs and symptoms of depression

The symptoms of depressive disorders will vary based upon individual genetic makeup, presence of co-occurring disorders, and severity of symptoms. The most common symptoms of depressive disorders include:

Behavioral symptoms:

  • Loss of interest in once-pleasurable activities
  • Angry outbursts over even the smallest of matters
  • Loss of interest in sex
  • Withdrawing from friends and loved ones
  • Spending increasing amounts of time alone

Physical symptoms:

  • Changes in eating patterns
  • Weight loss or gain
  • Changes in sleeping patterns – insomnia or hypersomnia
  • Fatigue, tiredness
  • Lack of energy
  • Slowed general body movements

Cognitive symptoms:

  • Slowed thinking
  • Slowed speaking
  • Difficulty concentrating
  • Trouble thinking clearly
  • Challenges with decision making
  • Unexplained physical problems such as back pain or headaches

Psychosocial symptoms:

  • Persistent sad mood
  • Feeling empty inside
  • Unhappiness
  • Anxiety
  • Agitation
  • Restlessness
  • Feelings of worthlessness or guilt
  • Fixation on past failures
  • Blaming themself for events outside of their control
  • Frequent thoughts of death
  • Suicide attempts
  • Self-harm

Effects of Depression

Common effects of depression

Left untreated, this highly treatable mental disorder can lead to very serious complications in nearly every facet of a person’s life. Depressive disorders can take a tremendous toll, leading to emotional, behavioral, and physical health problems. Complications of untreated depressive disorders include:

  • Excess weight and/or obesity
  • Alcoholism or substance abuse
  • Anxiety disorders – panic disorder, social phobia
  • Familial problems
  • Interpersonal relationship problems
  • Difficulties maintaining responsibilities at home, work, or school
  • Social isolation
  • Suicidal ideation
  • Self-harming behaviors
  • Premature death

Co-Occurring Disorders

Depression and co-occurring disorders

Depressive disorders are often accompanied by other types of mental disorders. The most common co-occurring disorders include:

  • Anxiety disorders
  • Post-traumatic stress disorder
  • Alcohol or other substance use
  • Anorexia nervosa
  • Bulimia nervosa
  • Borderline personality disorder