Depression is a condition in which a person feels discouraged, sad, hopeless, unmotivated, or disinterested in life in general. When these feelings last for a short period of time, it may be a case of  “the blues.”

But when such feelings last for more than two weeks and when the feelings interfere with daily activities such as taking care of family, spending time with friends, or going to work or school, it’s likely a major depressive episode.

Major depression is a treatable illness that affects the way a person thinks, feels, behaves, and functions. At any point in time, 3 to 5 percent of people suffer from major depression; the lifetime risk is about 17 percent.

What are some of the symptoms of depression?
The symptoms and severity of feelings of depression may be different for each person. A person experiencing a depressive episode may display physical and psychological symptoms including:

• Persistent feelings of sadness, anxiety and hopelessness
• Eating or sleeping too much or too little, including frequent waking during the night
• Loss of interest in daily activities, a lack of energy and/or loss of sex drive
• Excessive crying and/or thoughts of suicide
• Restlessness, agitation and irritability
• Difficulty concentrating, remembering, making decisions
• Feelings of guilt or worthlessness

Source: Beyondblue; Mental Health Information Service.

Types of depression
Adjustment Disorder with Depressed Mood – depression is triggered by stressful situations requiring change e.g. loss of a job, relationship break-up or “positive” changes e.g. travel, marriage, new job, etc

Major depression involves at least five of these symptoms for a two-week period. Such an episode is disabling and will interfere with the ability to work, study, eat, and sleep. Major depressive episodes may occur once or twice in a lifetime, or they may re-occur frequently. They may also take place spontaneously, during or after the death of a loved one, a romantic breakup, a medical illness, or other life event.

Dysthymia is a less severe, long-term, and chronic form of depression. It involves the same symptoms as major depression, mainly low energy, poor appetite or overeating, and insomnia or oversleeping. It can manifest as stress, irritability, and mild anhedonia, which is the inability to derive pleasure from most activities.

People with dysthymia might be thought of as always seeing the glass as half empty.

Bipolar disorder, once called manic-depression, is characterized by a mood cycle that shifts from severe highs (mania) or mild highs (hypomania) to severe lows (depression).

During the manic phase, a person may experience abnormal or excessive elation, irritability, a decreased need for sleep, grandiose notions, increased talking, racing thoughts, increased sexual desire, markedly increased energy, poor judgment, and inappropriate social behaviour.

During the depressive phase, a person experiences the same symptoms as would a sufferer of major depression. Mood swings from manic to depressive are often gradual, although occasionally they can occur abruptly.

Depression and anxiety disorders: not the same
Depression and anxiety disorders are different, but people with depression often experience symptoms similar to those of an anxiety disorder, such as nervousness, irritability, and problems sleeping and concentrating. But each disorder has its own causes and its own emotional and behavioural symptoms.

Many people who develop depression have a history of an anxiety disorder earlier in life. There is no evidence one disorder causes the other, but there is clear evidence that many people suffer from both disorders.

Source: Beyondblue; Mental Health Information Service