Is there a relationship between IQ and adverse childhood experiences?

Note: This is a section of a longer article. To go to the start, click here.

Not really. We asked our participants whether they experienced a variety of  potentially traumatic  experiences in their childhood (prior to your 18th birthday) based on the Adverse Childhood Experiences (ACEs) questions. In particular, we asked them the following ten yes/no questions about their childhood:

1. Did a parent or adult in your home often swear at you, insult you, or put you down?

2. Did a parent or adult in your home ever hit, beat, kick, or physically hurt you in any way?

3. Did you experience unwanted sexual contact (such as fondling or oral/anal/vaginal intercourse/penetration)?

4. Did you feel that no one in your family loved you or thought you were special?

5. Did you feel that you didn’t have enough to eat, had to wear dirty clothes, or had no one to protect or take care of you?

6. Did you lose a parent through divorce, abandonment, death, or other reason?

7. Did your parents or adults in your home ever hit, punch, beat, or threaten to harm each other?

8. Did you live with anyone who had a problem with drinking or using drugs, including prescription drugs?

9. Did you live with anyone who was depressed, mentally ill, or attempted suicide?

10. Did you live with anyone who went to jail or prison?

Correlations between IQ and responses to all of these questions were basically negligible, with the one between IQ and having lived with someone who went to prison being the only one higher than 0.10 in absolute terms (but it was still small, with r = -0.12, n = 684; this corresponds to a five-point IQ difference between people who did and did not live with anyone who went to prison, after statistically adjusting IQ for the effects of age, gender and data source). In addition to this, we have also created a total ACE score by summing up all the adverse experiences that a participant reported, essentially tracking how many, out of the ten possible adverse experiences, did each participant have. This total ACE score was also not related to IQ ( r = -0.01). Thus, it seems that having a range of difficult experiences in childhood does not have a meaningful relationship to  later life IQ. 

What do the other studies say?

It seems that our results differ from those in the academic literature, as several studies that we found in the literature indicate that childhood trauma exposure can negatively impact cognitive development and academic performance. Several studies have found associations between interpersonal trauma in childhood and decreased IQ scores that persist into later childhood and adulthood (Bosquet Enlow et al., 2012; van os et al., 2017). Similarly, violence exposure and trauma-related distress in young children have been linked to substantial decrements in IQ and reading achievement (Delaney‐Black et al., 2002). 

Takeaways

• In our study, childhood adverse experiences had little to no association with adult IQ, but it must be noted that other studies found that these traumatic experiences are associated with  detrimental effects

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