Symptoms of depression

Depression is a mental illness with a common but varied set of symptoms. Every person suffering from depression is affected in a unique way, and the effects can often change over time. Generally, you feel sad and miserable for most of the time and your mood is persistently very low.

Depression is more than just sadness

Some people use depression as a label to refer to any kind of ongoing sadness. This doesn't match the medical definition of clinical depression but isn't necessarily unhelpful - most people will understand the general idea of what you're trying to communicate. However, in recent years labelling a low mood as depression has become accepted in many areas of society. It is not uncommon to hear an offhand comment such as "I am feeling so depressed today" when the person is just having a tough day. Using that label is not invalid, but it is important to understand the difference between depression and sadness when trying to help someone who is affected - whether yourself or a loved one.

If you're depressed the symptoms will often last for a long time - weeks or months at a time. Some people can fall into depression quickly - especially after a traumatic event, while others can slowly slip into stronger symptoms. The symptoms may always be present in some cases, but some pople will have periods of depression separated by days, months or even years.

What are the signs of depression?

Depression can be difficult to observe correctly. For some people, depression can look very similar to ongoing sadness or low mood, and may be downplayed or ignored. In others, symptoms can be covered by other conditions or afflications - such as anger or alcoholism.

Common signs of depression include:

  • Constant tiredness and lack of energy
  • Sleeping too much or too little
  • Feeling helpless, hopeless, or worthless
  • Loss of appetite or overeating
  • Difficulty thinking, concentrating or making decisions
  • Loss of interest or pleasure in activities once enjoyed
  • Sadness or emotional 'numbness'
  • Poor concentration
  • Feeling guilty, or crying for no apparent reason.

Some medical conditions such as thyroid problems, brain tumors or vitamin deficiency can mimic symptoms of depression so it is important to rule out general medical causes.

Clinical definition of depression

In the United States, clinical depression is defined as a mental disorder in DSM-5, a tool for psychiatric diagnoses. It is known as Major depressive disorder (MDD).

According to DSM-5, for a diagnosis of depression the patient must present at least five of the following symptoms for at least two weeks:

  • Fatigue or loss of energy almost every day
  • Feelings of worthlessness or guilt almost every day
  • Impaired concentration, indecisiveness
  • A sense of restlessness or being slowed down
  • Significant weight loss or weight gain