Causes & Effects of Adult Depression

Understanding Depression

Learn about depression

Although it is normal and healthy to experience sadness from time to time, men and women with depression experience sadness to such a degree that it prevents them from living their lives. Depression is not just a short period of sadness; depression is instead a long-term feeling that the world is gray and unappealing. Adults with depression often lose interest in things they used to enjoy and may feel unmotivated, tired, or apathetic.

Depression can have serious negative effects on a person’s life. Although things can feel hopeless, depression is very treatable, and sufferers can often dramatically improve their lives if they seek help.


Statistics for depression

About 16 to 18 million people in the United States struggle with depression. Unfortunately, despite the fact that depression is treatable, only about 20 percent of depression sufferers seek help. Depression can occur across the lifespan, but it is most common in adults aged 18 to 25. Despite the fact that nearly two-thirds of people with depression will not even realize they have it, researchers estimate that depression will become the second most common cause of disability worldwide within the next 20 years.

Causes & Risks

Causes & risk factors of depression

The causes and risk factors for depression in adults are complex and not fully understood. Researchers suggest that an adult’s vulnerability to depression arises out of both genetic and environmental factors. Some research suggests that an imbalance of certain neurotransmitters, such as serotonin, may be partly to blame for depression in adults. Sometimes other hormonal imbalances, such as hypothyroidism, may also produce depressive symptoms. The most promising research exploring why some adults experience depression while others do not is in the field of epigenetics, which studies how certain environmental influences can switch on or switch off certain clusters of genes.  Consider the following causes and risk factors for adult depression:

Genetic: Depression, like most mental illnesses, tends to run in families. In families with one parent who has depression, children are 30 percent more likely to develop the disorder throughout their lifespans. A person’s chance of depression rises to 60 percent when both of his or her parents suffer from depression.

Environmental: Although some people may be born with a higher risk or genetic vulnerability to depression, not every man or woman with this vulnerability develops the disorder. Certain elements of a person’s environment also play a role. For example, undergoing significant life stressors, such as death of a loved one, abuse, trauma, relocation, divorce, and chronic stress, can bring about the symptoms of depression. These difficult circumstances do not always cause depression, suggesting that neither environment nor genetics is solely responsible for a person’s depression. It is most likely that the emergence of depression is due to a mix of genetics, temperament, and environment.

Risk Factors:

  • Gender; women are more likely to suffer from depression, though some evidence suggests that many men battle this disorder but do not seek treatment
  • Family history of depression, substance use, or other mental illness
  • Personal history of mental illness or substance use
  • Experiencing severe chronic stressors, such as health problems, poverty, or long-term unemployment
  • Experiencing major life transitions, such as moving, divorce, death of a loved one, or injury

Signs and Symptoms

Signs & symptoms of depression

Depression manifests in many forms depending on the individual person and the nature of the particular depressive disorder. Some people may be able to remain more or less functional but feel unmotivated, unfocused, lethargic, or apathetic. Other people may struggle to even get out of bed. Although each person’s experience of depression is unique, below are some of the more common signs and symptoms of depression in adults:

Behavioral symptoms:

  • Declined participation in activities that were once enjoyed
  • Poor occupational performance
  • Missing work
  • Failing to fulfill roles at home or at work
  • Displaying emotional outbursts
  • Engaging in self-harming behaviors

Physical symptoms:

  • Weight gain or loss
  • Unexplained aches and pains
  • Sleep disturbances
  • Appetite changes
  • Change in sex drive
  • Slowed movement

Cognitive symptoms:

  • Distractibility or difficulty focusing
  • Slowed thinking
  • Difficulty making decisions
  • Focusing on guilt, past mistakes, or poor self-worth

Psychosocial symptoms:

  • Sad mood
  • Unexplained tearfulness
  • Withdrawing from relationships
  • Feeling numb or disconnected
  • Thoughts of self-harm or suicide


Effects of depression

If left untreated, depression can have severe negative effects on a person’s life, ranging from poor work performance to death if one completes a suicide attempt. The effects of depression on an adult can include the following:

  • Deteriorating health and subsequent risk of physical ailments
  • Strain on relationships
  • Divorce
  • Injury as a result of engaging in dangerous or risky behaviors
  • Death or serious injury from suicide attempts

Co-Occurring Disorders

Depression and co-occurring disorders

Adults suffering from depression may meet criteria for other disorders, including:

  • Substance use disorders
  • Attention-deficit/hyperactivity disorder
  • Post-traumatic stress disorder
  • Eating disorders
  • Anxiety disorders
  • Obsessive-compulsive disorder
  • Personality disorders

When I came to Keystone, my depression had me at an all time low. But they helped me dig my way out of the hole I felt my life had become. Now I keep my mental health while living the kind of life I wanted.

– Anonymous Patient

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