Childhood Trauma: The ACE (Adverse Childhood Experiences) Study

The Adverse Childhood Experiences Study (ACE Study) is a research study conducted by the American health maintenance organization Kaiser Permanente and the Centers for Disease Control and Prevention.

Essentially, this study demonstrated that the more traumatic our childhood was, the more risk we are at of developing adult illnesses, both PHYSICAL and MENTAL.

Specifically, the study found that the more CHILDHOOD ADVERSE EXPERIENCES (ACEs) we suffered as children, the greater our risk of developing adult illnesses.

The study focused on the following childhood ADVERSE EXPERIENCES:

– physical abuse

– emotional abuse

– sexual abuse

– witnessing the mother being abused by the father

– loss/abandonment/rejection by a parent (including due to separation and divorce)

– living with a parent suffering from a pathological addiction

– living with a clinically depressed mother

– living with a mother who suffers from another significant mental illness

Effects Of Such Adverse Effects :

It has been found that such adverse experiences during our childhood can lead to highly damaging effects that may be extremely detrimental to our adult health. I list the main ones below:

– harmful effects on the physical development of our brain leading to architectural brain abnormalities 

– detrimental effects upon the brain’s functionality

(N.B: However, the good news is that such damage can be reversible).

– adverse effects upon how our genes express themselves (genes do not express themselves in a vacuum; their expression is affected by the environment in which they exist)

– damaging effects on the operation of our stress hormones (e.g. cortisol). This can lead us to become acutely reactive to the negative effects of stress in our adult lives resulting in a proclivity for us to react with great volatility and violence (in some cases, literally) in response to such stress (even stress that others may easily be capable of taking in their stride.

– an increased risk of serious physical diseases such as heart disease

Other Types Of Trauma:

I have already listed, above, the types of trauma that the ACE Study focused upon. However, continued research is demonstrating that is there traumatic childhood experiences, too, can impinge detrimentally upon both our physical and mental adult health; these include the following:

– growing up in severe poverty

– growing up environments in which there is little stimulation

– parental neglect (including emotional neglect)

– growing up in a violent environment

– growing up in an environment in which gang culture predominates

– being bullied at school

(The above list is NOT exhaustive)


ACEs that take place during the critical and sensitive developmental period of the person’s childhood (especially during the first three years of life and during puberty and early adolescence), coupled with their effects upon the person’s genetic expression (how our genes express themselves depends upon how they interact with our experiences/environment – this is known as epigenetics) can adversely affect brain development on a number of levels (see below):

ACEs Can Adversely Affect Brain Development On A Number Of Levels :


In turn, these adverse effects, taken together, can damage the brain upon both a STRUCTURAL and FUNCTIONAL level.


These brain changes then become hardwired in the brain’s biology as the behaviors that these brain changes are associated with are, on a fundamental level, ADAPTIVE AND ‘INTENDED’ TO HELP THE CHILD SURVIVE HIS/HER TRAUMATIC ENVIRONMENT. 

For example, certain brain changes caused by the child’s traumatic experiences may predispose the child to hypervigilance and explosive outbursts of rage and anger, both of which are adaptations that enhance survival chances in a dangerous, threatening, and hostile environment. Indeed, children who grow up in traumatically threatening environments are at significantly increased risk of developing OPPOSITIONAL DEFIANCE DISORDER (ODD).


The original ACE study found that overall and on average, the greater the number of ACEs an individual had experienced during childhood, the more likely s/he was to suffer from the following problems later in life :




NB: The above list is NOT exhaustive.

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David Hosier BSc Hons; MSc; PGDE( FAHE). is reader-supported. When you buy through links on this site, I may earn an affiliate commission.