While the causes of depression are complex, there is a growing body of evidence that links abuse in childhood with depression symptoms later in life. In many people, child abuse causes not only immediate physical and psychological damage, but it can also lead to long-term health problems.
Adults who were abused or neglected as children may be more likely to suffer from depression, post-traumatic stress disorder and antisocial personality disorder. These people may also be at increased risk for substance abuse problems, sexual problems and housing difficulties. In some cases, physical or sexual abuse in childhood causes physical changes in the brain that predispose abuse survivors to depression.
Child Abuse, Depression and Sexual Abuse
The link between child abuse, depression and other problems has been known for many years. In a 1998 study published in the British Medical Journal, Irish researchers reported that women who had experienced severe sexual abuse commonly had adult depression symptoms.
In the study, women who experienced the most severe abuse had statistically significant rates of depression. The researchers defined severe abuse as either sexual penetration or attempted penetration. All of the women who suffered penetration during child abuse experienced adult depression, and roughly 87 percent of those who suffered attempted penetration were depressed. Women who had been sexually abused were also more likely to report having sexual problems, housing difficulties and problems with their children at school.
A study published in the Archives of General Psychiatry in January 2007 reported that abused or neglected children had higher than normal rates of major depression. They were also more likely to display symptoms of a series of other mental disorders in addition to major depression, including:
- Antisocial personality disorder
- Drug dependency
- Post-traumatic stress disorder.
In contrast to the British Medical Journal findings, the U.S. study did not find a correlation between sexual abuse and major depression, although survivors of sexual abuse reported more depression symptoms than normal. This may be due to differences in the two studiesÃ• demographics. The U.S. study examined depression in both sexes and across a wider range of child abuse and neglect than the Irish study, which focused specially on female survivors of sexual abuse.
Child Abuse, Depression and the Stress Response
Child abuse causes permanent changes to the brainÃ•s DNA, according to a Canadian study published in the February 2009 issue of Nature Neuroscience.
As part of the study, researchers performed postmortem examinations of brain sampled from 36 suicides. Of these participants, 12 had been abused as children. The researchers discovered that the brains of people who experienced child abuse had genetic changes to an area of the brain that controls the hypothalamic-pituitary-adrenal function, a portion of the brainÃ•s stress response.
The genetic material itself was unchanged. However, genes are chemically modified via DNA methylation, which affects how that DNA participates in biosynthesis. Child abuse appears to change the way DNA methylation processes function, causing mental health issues later in life.
Cheasty, M., Clare, A. and Collins, C. (1998). Relation between sexual abuse in childhood and adult depressionÃ“ case-control study. Retrieved May 4, 2010, from the British Medical Journal website: www.bmj.com/cgi/content/full/316/7126/198.
Medical News Today Staff. (2009). Child abuse causes lifelong changes to DNA expression and brain. Retrieved May 6, 2010, from the Medical News Today website: www.medicalnewstoday.com/articles/139938.php.
National Institute of Mental Health Staff. (2010). History of childhood abuse or neglect increases risk of major depression. Retrieved May 4, 2010, from the National Institute of Mental Health website: www.nimh.nih.gov/science-news/2007/history-of-childhood-abuse-or-neglect-increases-risk-of-major-depression.shtml.
Nauert, R. (2007). Childhood abuse linked to migraines and depression. Retrieved May 4, 2010, from the Psych Central website: psychcentral.com/news/2007/09/05/childhood-abuse-linked-to-migraines-and-depression/1229.html.