It has long been established that childhood trauma increases a person’s risk for developing depression and addiction later in life. Now, a small study of teens from the University of Texas offers one possible explanation.
The findings reveal that childhood suffering triggers a disruption in particular neural networks which are linked to a greater chance of developing substance abuse problems, depression or both in teens.
Researchers studied 32 teens, 19 of whom had experienced childhood trauma but were not diagnosed with a current psychiatric disorder. In the study, childhood trauma was defined as any type of significant abuse or neglect lasting six months or longer, or a major traumatic experience like a life-threatening illness, witnessing domestic violence or losing a parent before age 10.
The remaining 13 individuals in the study served as the control group, having no history of major child trauma or psychiatric problems.
The teens had a follow-up every six months for an average of 3-1/2 years. During that period, five of the abused children and one control had developed major depression and four of the maltreated children and one control had developed substance use disorders. Two of the maltreated children had both a drug problem and depression.
Therefore, half of the maltreated children had a either a diagnosable drug problem or depression or both—three times the rate of the control subjects.
For the study, researchers searched for any differences in the teens’ brains when they first enrolled in the study (before they had developed any psychiatric problems) using a brain-imaging technique that measures the integrity of white matter that connects various brain regions.
The scans revealed that those who had been maltreated had connectivity problems in several brain areas, including the superior longitudinal fasciculus (SLF), which is involved in planning behavior and language processing.
The right cingulum-hippocampus projection (CGH-R) was another affected brain region. This area helps connect the brain’s emotional processing regions with those involved in more abstract thought, so that the person can integrate both types of information and keep a regulated response to emotional stress.
Those who developed depression showed the largest reductions in white matter in their SLF; whereas those who developed drug problems seemed to have greater white matter loss in the CGH-R.
This suggests that a vulnerability to depression may be associated with rumination and a processing of language that is focused on negative thinking, while addiction susceptibility may be linked to an inability to regulate emotions.
Since earlier research has found reduction in different white matter regions among abused children — and because this was a small study — more research is needed before any set conclusions can be drawn.
However, the findings add to the idea that addiction problems have more to do with people trying to manage or run from pain rather than a desire to experience pleasure — and that simple drug exposure is not enough in itself to trigger addiction.
The study was published in Neuropsychopharmacology.