According to a new study, the risk of developing multiple episodes of clinical depression in a child or teenager is nearly doubled if that person is the subject of abuse.
The episodes also appear to be longer-lasting in such people, and they appear to less likely to respond to treatment. The new study was led by a team of researchers from King’s College London Institute of Psychiatry.
Depression ranks among the most common mental disorders in the world, with about 1 in 15 adults suffering from depression in the U.S. in any given year. About 1 in 12 teens suffer from depression in the U.S.
By 2020, depression is predicted to be the second leading contributor to the global burden of disease across all ages, according to the World Health Organization. The societal impact of depression is largely accounted for by individuals who develop multiple and long-lasting depressive episodes.
The current researchers reviewed 16 previously published studies in scientific and medical journals, on a total of more than 23,000 patients.
The new research found that maltreatment in childhood — such as rejection by the mother, harsh physical treatment or sexual abuse — more than doubled the risk of depression.
A separate review on over 3,000 patients showed that childhood maltreatment was also linked to a poorer response to both drug and psychotherapy treatment.
“Even for combined treatments, patients with a history of childhood maltreatment cannot be adequately cared for,” noted lead researcher Andrea Danese.
Out of the 23,000 study participants, researchers found that 27 percent were noted as having “probable” maltreatment, and 19.4 percent then went on to developed persistent depression. A smaller group of 9 percent had “definite” maltreatment, and of those patients, 31.5 percent then went on to develop depression. Most people in the study — 64 percent — had no maltreatment, and only 12.5 percent of them went on to develop depression.
Childhood maltreatment, according to previous research, causes changes to the brain, immune system and some hormone glands. Some of these changes stay with those abused well into adulthood.
“Identifying those at risk of multiple and long-lasting depressive episodes is crucial from a public health perspective,” noted the researchers.
“The results indicate that childhood maltreatment is associated both with an increased risk of developing recurrent and persistent episodes of depression, and with an increased risk of responding poorly to treatment.
One possible mechanism is what is known as epigenetic changes to the DNA. While there is no change in the genetic code, the environment can alter the way genes are expressed.
“Therefore prevention and early therapeutic interventions targeting childhood maltreatment could prove vital in helping prevent the major health burden owing to depression. Knowing that individuals with a history of maltreatment won’t respond as well to treatment may also be valuable for clinicians in determining patients’ prognosis.”
The study appears in the latest issue of American Journal of Psychiatry.
Source: King’s College London Institute of Psychiatry