Article summary of Adverse childhood experiences and the consequences on neurobiological, psychosocial, and somatic conditions across the lifespan by Herzog & Schmahl - Chapter

Preface

Neglect, physical -and sexual abuse are known as adverse childhood experiences (ACE). In Europe, community surveys show high rates of emotional, sexual and physical abuse. However, most cases are still underreported. ACE’s frequently play a massive part in the development of long-lasting adverse effects on the brain, but also on mental and physical health. This is because they influence cognitive -and affective processing. ACE’s influence brain processes in the amygdala, hippocampus and anterior cingulate cortex (ACC) that regulate emotional, cognitive -and affective processing. The current review presents the literature on the influence of adverse childhood experiences on mental health, neurobiology and somatic health later in adulthood. The study reviewed several articles on the influence of ACE on adulthood neurobiology, somatic -and mental health.

What are structural brain alterations caused by ACE?

ACE’s can alter sensitivity to stress -and emotion regulation. The hippocampus and amygdala are vulnerable to ACE because of the high density of glucorticoids that can cause damage to dendritic atrophy and neurogenesis suppression. Several neuroimaging studies found that the size of the hippocampus is reduced of individuals that experienced ACE. Furthermore, the amygdala consists of pyramidal cells that are highly susceptible to the effects of stress. Stress stimulates the process of dendritic arborization which causes an increase of the size of the amygdala. However, this is almost always related to only physical neglect. On the other hand, people suffering form bipolar disorder show an increased volume of the amygdala.  

What is the role of type and timing of exposure?

The exposure to specific types of childhood experiences affect certain sensory systems. These sensory systems are involved with trauma. Domestic violence for example, targets the inferior longitudinal fasciculus that interconnects the limbic and visual systems. The effect of domestic is most critical when it happens between the age of 11-13 years. For sexual abuse however, the most susceptible age is between 3-5 years.

What are functional brain alterations caused by ACE?

Functional neuroimaging studies show the functional brain alterations. The amygdala is critically involved in processing and detecting salient stimuli. The amygdala is hyperactive when exposed to danger or emotional stimuli. This hyperactivity is associated with a greater risk for posttraumatic stress disorder (PTSD), anxiety -and mood disorders. Besides the amygdala, the anterior insula is hyperactive in individuals with ACE while exposed to emotion -and attention stimuli. This hyperactivity could be an adaptive ability in the context of childhood abusive experiences.

What are the consequences of ACE?

There are many effects of ACE on the development of different clinical profiles in adulthood. Somatic -and mental disorders can co-occur in posttraumatic stress disorder, depression, borderline personality disorder, obesity and diabetes. The risk for developing a mental illness after ACE is the highest for PTSD, depression, borderline and substance abuse. People with mental disorders with ACE are less likely to respond to standard treatments. Some ACE’s have a bigger effect on mental health than others. A general effect of stress was found on neural alterations and development of disorders.

The innate immune system seems to be a biological mediator between ACE and diseases in adulthood. This is true for obesity, Crohn disease and diabetes. An association between an increase of pro-inflammatory markers and ACE was found. This is also true for C-active -and other proteins. ACE are known to be associated with chronicity of low back pain, pain sensitivity and enhanced temporal summation of pain.

There is a role of type of ACE and timing that should be considered in the prevention and treatment of ACE-related mental -and somatic illnesses. During the vulnerable development stages of childhood, the risk of getting a ACE-related condition increases. There are sensitive periods that correlate with a specific type of ACE. During these periods, people are prone to develop neural alterations and functional changes in the amygdala and hippocampus. However, there is a mediating effect of familiar support in the development of a disorder even when exposed to ACE.

What did the researchers conclude?

There are more longitudinal studies needed to research the complex and ACE-related characteristics and mechanisms relevant for mental -and somatic disorders by the integration of fitting knowledge and methods. Psychological treatment options can be improved by a better identification and validation of psychosocial and somatic risk factors and diagnostic markers.