Why does a life-threatening experience lead to post-traumatic stress disorder (PTSD) in some people but not others? According to Karestan Koenen and colleagues, at least part of the answer lies in the kind of childhood they had.
The researchers have assessed the same group of 980 people every few years since they were born in New Zealand between 1972-73. When the participants were aged 32, the researchers asked them if they’d had a terrible or frightening experience since they were aged 26 (239 had), and whether they subsequently developed symptoms indicative of PTSD (35 of them had).
Participants who had low IQ as children, who exhibited childhood antisocial behaviour, and who were from poorer families, were more likely to have developed PTSD after a traumatic experience in adulthood. These factors had a cumulative effect, so those who had more than one of the childhood risk factors were even more likely to have developed PTSD after a trauma.
The researchers believe participants who had a lower childhood IQ may have lacked the cognitive resources as adults needed to translate their traumatic event into a narrative. Meanwhile, the participants who showed antisocial behaviour in childhood may have had poor self-regulation, and so lacked the emotional tolerance necessary for processing the traumatic event. Finally, a poorer family background could indicate a less stable childhood environment, which from animal research is known to have an effect on hormone and neurotransmitter regulation in the brain, thus increasing susceptibility to PTSD.
The researchers said clinicians could benefit from taking their clients’ childhood cognitive and temperamental characteristics into account. “In fact”, they wrote, “psychotherapy that combines a developmentally informed approach…with more traditional trauma-focused treatment has been shown to be highly effective in treating adult PTSD”.
Koenen, K.C., Moffitt, T.E., Poulton, R., Martin, J. & Caspi, A. (2007). Early childhood factors associated with the development of post-traumatic stress disorder: results from a longitudinal birth cohort. Psychological Medicine, 37, 181-192.