We know the effects of childhood traumas like abuse and neglect on later substance abuse. But what impact does second hand trauma have? A study published in the August issue of the journal Addiction shows that when a child under age 15 is exposed to a family member’s trauma (e.g. a parent or sibling being the victim of violent assault or a parent’s cancer diagnosis), that child has approximately twice the risk of struggling with drug and alcohol problems 6 years later. 

The data comes from 1.4 million children born in Sweden between 1984 and 1995. Researchers used codes from the Swedish Hospital Discharge Register to discover which of these children had family members that had experienced medical trauma. Specifically, researchers could tell from these codes when a child’s parent or sibling had been diagnosed with cancer, had suffered an injury leading to permanent disability, had been the victim of an assault, or had died. Using these four events, researchers gave each of these 1.4 million children a score from 0-4 roughly representing the amount of secondhand trauma children had experienced while young.

From medical, legal and pharmacy records, researchers could also tell which of these children went on to be diagnosed with substance abuse problems in their 20s.

Of course, the researchers tried to control for all of the many factors that might also cause drug use in populations that also happened to experience childhood trauma. For example, they took into account things like socioeconomic status, drug use in the family, psychological wellbeing, and parents’ education.

What levels of trauma led to what levels of substance abuse? Not only kids who scored a “4” on the scale of traumas, but even kids who experienced one of these secondhand traumatic events had twice the risk of later drug abuse.

As you might expect, children who experienced the death of a parent were at greatest risk. This was followed by children whose parent or sibling had been the victim of violent assault – and the researchers point out that the fact of assault in many cases may be due to what they call an “underlying behavior type” that is associated with the risk of assault. Permanent disability due to injury and cancer diagnosis were also significant risk factors.

Interestingly, substance abuse was even higher in children whose siblings had experienced trauma than it was in children whose parents had been traumatized.

Though the researchers are careful to point out the difficulty of disentangling trauma from environment – meaning children who experience a family member’s trauma may be surrounded by other environmental factors that also promote drug abuse – they also point out that their sample size of 1.4 million children allows them to draw strong conclusions from this data.

It seems that in addition to the known risk factors of abuse, neglect and other traumatic events that a child experiences directly, the indirect or secondhand traumas a child experiences can lead to later substance abuse.


Richard Taite is founder and CEO of Cliffside Malibu, offering evidence-based, individualized addiction treatment based on the Stages of Change model. He is also coauthor with Constance Scharff of the book Ending Addiction for Good.