Depression Causes, Signs, Symptoms & Side Effects

No one experiences depression the same way as someone else. Understanding the signs, symptoms and side effects of depression is a key component toward starting the recovery journey.

Understanding Depression

Learn about depression

Often, when our mood is positive, we take it for granted. However, when our mood is negative, we’re more apt to notice it. Everyone has negative moods sometimes. Frequently they’re caused by something in our life such as the break-up of a romantic relationship or learning that we didn’t get the job we wanted. Even when a negative mood seems to affect our daily functioning, we eventually cope with the negative event and move forward with our lives.

However, for some people, it’s far more serious. Some people experience a type of negative mood that is more severe and long-lasting than a bad mood caused by a relatively normal type of life stress. This is when someone moves from having a normal reaction to a negative situation to experiencing depression.

Depression can significantly impact your life, the way you think, the way you feel, and the way you behave. Depression goes far beyond feeling sad or upset over something in the short-term or a reaction to something negative that happens. Depression affects your mood, thoughts, feelings, behaviors and physical health. Severe depression can result in losing the ability to feel pleasure in the things you once enjoyed. It can also cause you to withdraw from your social relationships even from people to whom you are closest.

Most people with depression experience a loss of energy and lack of motivation that can negatively influence your life. You may find it challenging to be productive at work or do well in school. If left unmanaged, depression can become so severe that some people feel unable to function in many major areas of their life.

Clinical depression is a serious illness that often needs long-term treatment to manage. Despite this, there are treatments for even severe depression that can enable you to enjoy life again.


Depression statistics

Approximately 7% of the U.S. population suffers from depression. This rate varies according to gender and age. Overall, women are 70% more likely to suffer from depression during their lives than men. Regarding age, individuals aged 18–29 are significantly more likely to suffer from depression than are individuals over the age of 60. The most common age of onset is during your 20’s although depression can begin later in life, especially in men.

Causes and Risk Factors

Causes and risk factors for depression

There are a number of factors that have been identified as causes of depression. This includes:

Genetics – Depression has been found to run in families. Research suggests that the genetic contribution to depression is most likely caused by an interaction of genes not a single gene.

Physiological Predispositions – Some individuals are born with a physiological predisposition to develop depression. Whether depression develops or not depends on the environment. In particular, major life events and stressors may cause a depressive predisposition to be expressed.

Brain Structures – Differences in the size and shape of areas of the brain that are responsible for mood, sleep, and appetite have been found to cause depression. While researchers don’t currently know how this affects the development of depression, there is a strong link between these differences and depression.

Neurotransmitters – chemicals in the brain called neurotransmitters can affect mood. When levels of certain neurotransmitters are out of balance, this can result in depression.

Psychological Factors – Some people have a depressive way of thinking. For example, when something positive happens these individuals assume it’s due to the efforts of others. However, when something negative happens they assume that it was their fault. Some people may believe that others are always judging them unfavorably. Memory can also play a role in depression – in a situation that’s predominantly positive, some people only remember the few negative moments or remember neutral events as negative events.

Environmental Factors – There are many negative life events associated with the onset of depression. These include job loss, the death of a loved one, trauma, troubled relationships, and a lack of a positive social network. Any major stressors can lead to depression.

Overall, professionals have concluded that depression is caused by an interaction of genetic, physiological, psychological and environmental factors. Therefore, there are many combinations of factors that can lead to depression.

Signs and Symptoms

Signs and symptoms of depression

People with depression suffer from a variety of symptoms. These include:

Mood Symptoms

  • Depressed mood almost every day over the course of two years
  • Loss of interest in sexual activities or desire
  • Loss of interest or enjoyment in practically all activities
  • Sense of worthlessness or guilt with no reason
  • Sadness and unhappiness
  • Restlessness
  • Emotional outbursts
  • Irritability
  • Guilt
  • Shame

Physical Symptoms

  • Increase or decrease in appetite
  • Feeling emotionally numb
  • Increase or decrease in sleep
  • Lack of energy
  • Somatic complaints, in particular pain

Behavioral Symptoms

  • Slowed speech
  • Slowed thinking
  • Crying without any reason
  • Social Withdrawal
  • Loss of efficiency completing tasks
  • Distractibility
  • Psychomotor disturbances – agitation or slowed movement

Psychological Symptoms

  • Trouble making decisions
  • Hopelessness
  • Loss of self esteem
  • Concentration and memory problems
  • Lack of motivation
  • Thoughts of suicide or having a plan in place
  • Distractibility


Effects of depression

There are numerous ways depression can effect someone’s life. These include:

  • Poor coping skills
  • Alcohol or other substance abuse
  • Family/marital problems
  • Anxiety over feelings of loss in all areas of life
  • Social problems
  • Social isolation
  • Pain, especially headaches and stomach pain
  • Problems at work or school
  • Insomnia
  • Sexual dysfunction
  • Decreased immune system functioning which can lead to physical problems including premature death
  • Self- mutilation (e.g. cutting, burning)
  • Suicide

Co-Occurring Disorders

Depression and co-occurring disorders

Practically any non-mood related disorder increases the likelihood that an individual will also develop depression. Some of the most common co-occurring disorders include:

  • Alcohol and Substance Abuse Disorders – While substance abuse disorders do co-occur with depression sometimes these disorders may trigger depression. People with depression often self-medicate with drugs or alcohol to relieve their symptoms. This can in turn cause a substance abuse problem.
  • Anxiety disorders – (Post-Traumatic Stress Disorder, Obsessive-Compulsive Disorder, Panic Disorder, Social Phobia, and Generalized Anxiety Disorder) Depression rarely occurs without anxiety.
  • Borderline personality disorder – 96% of individuals diagnosed with borderline personality disorder also suffer from depression.
  • Eating disorders (Anorexia, Bulimia) – Being severely underweight or having a significant electrolyte imbalance for a long period of time can result in depression.