A variety of studies have shown that the risk for Post-Traumatic Stress Disorder (PTSD) is higher in individuals with Attention Deficit Hyperactivity Disorder (ADHD) compared to those without ADHD and the risk for ADHD is higher in individuals with PTSD than those without PTSD. The association has been noted to be bidirectional but the strongest correlation is for the risk of PTSD in individuals with ADHD – these individuals had nearly 4 times the risk of developing PTSD than those without PTSD. This clinical profile is true for both adult and child populations.
Given that the onset of ADHD is typically and consistently earlier than the onset of PTSD, it is thought that ADHD could be an antecedent risk factor for PTSD. The increased risk of PTSD in individuals with ADHD cannot be explained solely by an increased rate of trauma exposure in this population. While trauma is a fairly common phenomenon, only a minority of traumatized children develop clinically evident PTSD, and there is not a direct correlation between the severity of trauma and development of PTSD. Additionally, individuals with PTSD had twice the risk of ADHD compared to controls with similar trauma exposure. This supports the idea that individual who develop PTSD have predisposing risk factors that increase the chance of PTSD developing after exposure to trauma, and there is good evidence that ADHD might be one of those predisposing risk factors. There is concern that there is an increase in vulnerability to PTSD in individuals with more severe and longer-lasting ADHD symptoms.
The neurobiological mechanisms underlying this association are not well defined but emerging studies in neuroimaging and genetic research are starting to provide some clues. Neuroimaging studies have shown that irregularities in dopaminergic neurotransmission and prefrontal cortex dysfunction have been found in both ADHD and PTSD, leading to the possibility that abnormalities in specific neural circuits in ADHD may increase the vulnerability for both ADHD and PTSD. Genome-wide data has found substantial shared common genetic variation between these two disorders, and they also have some common specific genetic risk factors. Further research is needed to understand the clinical significance of these findings.
So what does all this mean clinically in a primary care setting? Awareness of this comorbidity between ADHD and PTSD alerts clinicians treating patients with one disorder to screen for the other. Additionally, the association between symptoms also suggests that PTSD symptoms can exacerbate ADHD symptoms and vice versa. Patients with PTSD can develop an acquired ADHD-like syndrome, which includes reports of inattention, disorganization, and forgetfulness—this most probably related to the cognitive strain associated with states of higher anxiety as demonstrated in studies showing that chronic uncontrollable stress impairs working memory and prefrontal cortex function. For individuals with clearly defined co-morbidity, adequate treatment of the anxiety symptoms would be a recommended first area for treatment focus, with awareness of the possible problem side effects of increased anxiety and hyperarousal states that may emerge with the use of stimulant medications to treat ADHD symptoms. Clinical experience supports the idea that in children with both PTSD and ADHD, the alpha-agonists can be helpful for both symptoms. Similar benefit with adult populations has also been reported.
References:
The Neuropsychological Profile of Comorbid Post-Traumatic Stress Disorder in Adult ADHD. J Atten Disord. 2016 Dec;20 (12):1047-1055. Epub 2014 Feb 24. Antshel KM1, Biederman J2, Spencer TJ2, Faraone SV3.
Examining the association between posttraumatic stress disorder and attention-deficit/hyperactivity disorder: a systematic review and meta-analysis. J Clin Psychiatry. 2016 Jan;77(1):72-83. doi: 10.4088/JCP.14r09479.
Spencer AE1, Faraone SV, Bogucki OE, Pope AL, Uchida M, Milad MR, Spencer TJ, Woodworth KY, Biederman J.