Depression

From The Australian Women’s Weekly Health Series: Depression. Buy the Book. What causes depression? Medical research indicates that for most people there is not a simple social, psychological or medical explanation for their depression. Instead, there is likely to be a complex interaction between internal and external factors. People who get depressed are more likely to have certain individual (or internal) factors such as past bad experiences, stronger family histories of depression and anxiety or certain unhelpful personality, thinking or coping styles.

Individual (internal) factors The types of past experience that often matter include a difficult early family life, poor relationships with parents or sexual abuse. Depression often runs in families, indicating both genetic and early home environment effects. The genetic contribution varies from family to family and in some families is very strong. Depression and anxiety are often underpinned by changes in key brain chemicals, such as serotonin, noradrenaline or dopamine. In addition to depression, anxiety, alcohol and other drug abuse, and suicidal behaviour also run in families.

Social (external) factors Depression and anxiety often don’t just come out of the blue. Although some acute life events (for example, job loss, marital separation) may precipitate a depressive episode it is just as likely that depression leads to many life difficulties such as poor work performance and marital disputes. Chronic life problems such as long-term unemployment, marital dysfunction or caring for a sick relative are more important social stressors than most acute life difficulties.

Alcohol and other drug abuse People often become depressed in the context of ongoing alcohol and other drug abuse. Many people develop problems with alcohol or drugs because they have had earlier problems with anxiety or some other psychological difficulty. The longer they use these drugs, however, the more likely they are to develop a significant depressive illness. After a few years it becomes irrelevant which problem came first.

Medical factors There are a series of medical conditions that are commonly associated with depression. Illnesses that affect the brain (such as stroke, Parkinson’s disease, multiple sclerosis, epilepsy and traumatic brain injuries) are particular likely to lead to depression. Other hormonal problems such as an underactive thyroid gland or hormonal treatments such as steroid medications may be associated with depression.