Abused children have double the risk of persistent depression

Abused children have double the risk of persistent depression

By Liz Lockhart

Researchers at the Institute of Psychiatry at Kings College, London say that childhood abuse doubles the risk of developing long-lasting episodes of depression which can occur on multiple occasions.

Their review is published in the American Journal of Psychiatry.  It also suggest that in these cases the patients are less likely to respond to treatment.

The study highlights how damaging childhood trauma can be.  Nearly one in 20 people in the UK has this form of depression as a consequence of abuse in childhood the researchers say.

Statistics vary on the number of people who are affected by depression at some point in their lives, one source quotes  that the number is one in five.    In the UK 16% of the population develops persistent depression by the age of thirty three.  A quarter of them were maltreated as a child, this equates to 4% of the whole UK population.

The study found that:-

• 64% had no maltreatment; of these 12.5% developed persistent depression
• 27% were "probable" maltreated; of these 19.4% developed persistent depression
• 9% had "definite" maltreatment; of these 31.5% developed persistent depression

Researchers were investigating depression which keeps recurring.  They reviewed 16 previous studies which involved more than 23,000 patients and found that maltreatment in childhood more than doubled the risk of this type of depression.  Maltreatment includes rejection by a mother, sexual abuse and harsh physical treatment.

Dr. Rudolf Uher, one of the Kings College researchers, said ‘If these things happen early in life, it is more powerful.’

In a separate review which involved 3,098 people, researchers found that childhood maltreatment was also linked to a   much poorer response to drug treatment.  This poor response was also found with psychological treatments.

The report suggests that ‘early preventive and therapeutic interventions may be more effective.  Dr. Andrea Danese, lead author, said ‘Even for combined treatments, patients with a history of childhood maltreatment cannot be adequately cared for.’

There does not appear to be any specific reason for any link between abuse, changes in the body as a child and persistent depression some 20 or more years later.  It is thought that childhood maltreatment causes changes to the immune system, some hormone glands and the brain.  Some of these changes  are still present in adulthood.

One possibility for this is epigenetic changes to the DNA.  While there is no change in the genetic code, the environment can alter the way genes are expressed. 

This research highlights how damaging trauma can be when experienced in childhood as this is a time when the brain is still developing.  It could lead to finding improved treatments and earlier prevention.