What is depression?

Depression is a condition characterised by low mood, negative views of oneself, the world, and the future, as well as a decreased ability to find pleasure from normally pleasurable activities. Depression can be caused by a chemical imbalance in the brain or by a reaction to a particularly upsetting situation. Depression can affect people of any age and may require treatment by a specialist.

What are the symptoms of depression? 

The signs and symptoms of depression can be behavioural, physical, emotional and cognitive. They include:

  • Loss of interest in pleasurable activities
  • Withdrawal from social activities
  • Feeling tired
  • Feelings of sadness, worthlessness, helplessness, guilt
  • Difficulty concentrating, making decisions
  • Weight change
  • Lack of motivation
  • Difficulty sleeping

How common is depression?

Depressive disorders constitute the second most prevalent cause of illness-induced disability worldwide, In Australia, approximately one million people suffer from depression each year, and around one in five will experience at least one episode of depression in their lifetime.

How is depression treated?

Depression can be treated with medication, cognitive therapy sessions, electroconvulsive therapy and community support programs.

 Treatment for depression

Depression facts and figures

  • 350 million people worldwide (5% of the population) suffer from depression
  • Leading cause of disability worldwide
  • 1 in 7 Australians will experience depression in their lifetime
  • 3rd highest burden of disease in Australia
  • Nearly twice as common in women than men

What causes depression?

The factors leading to depression can be viewed as contributing either to vulnerability or to stress; the marriage of these two may then be sufficient to cause severe depression.

Vulnerability comes either from genetic predisposition or in the form of early life experiences, such as abuse or inadequate emotional contact with parental figures. How vulnerable a person is sets the threshold for stress to trigger depressive events.

Stress can result from a major adverse life event (such as bereavement), or from multiple smaller triggers, such as unemployment, poverty, family disharmony or loneliness.

 Read more about depression and the brain

Depression research at QBI

Researchers at the Queensland Brain Institute (QBI) are making significant advances in the understanding of how anti-depressant medications work to stimulate the brain and improve a person’s mood.

In 2010, researcher Dr Dhanisha Jhaveri discovered that the class of drugs that increases levels of a neurotransmitter known as ‘norepinephrine’ triggers neurogenesis (the growth of new neurons) in a brain region called the hippocampus

“If you block hippocampal neurogenesis, antidepressants no longer work. That suggests antidepressants must up-regulate neurogenesis in order for them to actually have any affect on behaviour,” Dr Jhaveri said.

Armed with this information, researchers are now working to develop more specific – and therefore more effective – therapeutic treatments for depression.

“The identification of the molecular composition of receptors in the amygdala is guiding our search for new and more specific drugs to treat anxiety disorders,” explained anxiety researcher Professor Pankaj Sah