How Childhood Trauma Affects IQ and Its Development

Childhood trauma affects IQ by inhibiting normal cognitive development and reducing the ability to memorize, think logically, and make sound decisions. This happens due to intense and prolonged stress, which puts the brain into survival mode and shifts the focus away from cognitive functioning.

To better understand this phenomenon, our IQ experts have explored how specifically trauma affects intelligence, which parts of the brain are most susceptible to it, and what can be done to minimize its effects on cognition.

So, let’s dive into their findings.

Key Takeaways

• Childhood trauma and IQ are certainly correlated—traumatized children and adolescents usually have lower IQ scores than their counterparts from healthy environments.
• Childhood trauma affects intellectual development in general, as it shifts the brain’s focus almost entirely on survival.
• The areas of the brain most affected by trauma are the hippocampus and the prefrontal cortex, resulting in memory impairment, decreased emotional regulation, and poor decision-making.
• Early intervention can somewhat diminish the negative effects of trauma, as the brain’s neuroplasticity allows it to heal when given positive reinforcement.

How Trauma Affects a Child’s Cognitive Development

three kids playing

Trauma affects a child’s cognitive development by shifting the brain’s focus almost entirely on survival and neglecting functions such as memory, language, planning, and concentration.

This usually occurs when the child doesn’t have an adequate support system or when the primary caregivers, who should be a safe space, are actually the source of trauma.

In other words, if the parents are abusive, negligent, or violent toward each other in the child’s presence, the child is at risk of experiencing negative cognitive alterations.

It’s important to emphasize that children’s cognition won’t suffer from minor stressors—these are unavoidable and generally useful for growth and developing problem-solving skills. However, exposure to so-called toxic stress can cause trauma and stunt their intellectual development.

Toxic Stress and Its Effect on Cognition

Toxic stress is best understood through a comparison with tolerable stress—a stressor that can be quite damaging but isn’t due to a supportive environment and adult guidance.

For example, if children are injured or lose a loved one, they will experience a high degree of stress that could potentially harm their cognitive development. However, an adult they trust can mitigate the worst of it by helping them process their feelings and teaching them how to cope.

Unfortunately, some children don’t have such adults in their lives, so they have to bear the brunt of traumatic events by themselves. In such cases, there is no one to reassure them or help them regulate their response to stress. Consequently, these children experience toxic stress, which puts a significant strain on their brains.

More specifically, their brains enter a survival mode, elevating cortisol levels and increasing sensitivity to potential threats. Since this takes a lot of energy, there’s little to spare for developing the “less essential” abilities, like memory, focus, or logical thinking.

Furthermore, children affected by toxic stress learn that they can’t rely on adults, which creates a general sense of insecurity and lack of safety. This further exacerbates the problem—even when they are no longer experiencing trauma, they may still be in survival mode.

Does Childhood Trauma Decrease IQ?

Childhood trauma decreases IQ significantly, especially when it occurs in the very early stages of development. In fact, the first 24 months are crucial, as extreme exposure to stress during this period can lower the IQ by approximately 7.25 points.

This was observed in a longitudinal study conducted by Enlow et al., which aimed to evaluate how interpersonal trauma affects children’s IQ scores. The children, some of whom experienced maltreatment or witnessed domestic violence, were tested at two, five, and eight years, using assessment tools appropriate for their age.

The results were clear—childhood trauma and lower IQ scores went hand in hand. However, there was a marked difference between children who experienced trauma before the age of two and those who did later.

While early life trauma impacts IQ severely, the effect of toxic stress is less noticeable in preschool and school-aged children. The difference is still there, but it’s only a couple of points.

Community Violence and IQ

Aside from interpersonal trauma, community violence can have a significant negative effect on IQ and cognitive outcomes. According to the study by Delaney-Black et al., children can be affected even if they aren’t directly involved with the traumatic event.

For instance, if a child witnesses a robbery or murder, this will be reflected in their lower IQ scores and decreased reading ability. The child doesn’t necessarily need to feel traumatized for this to happen—even just witnessing can be enough.

However, researchers aren’t entirely sure if exposure to violence is the cause of lower IQ scores or the result.

Namely, some believe that children with low IQs are more likely to witness violence because they may not be as good at identifying potential threats and avoiding dangerous areas. Whatever the case, a correlation between the two certainly exists.

Can Childhood Trauma Increase IQ?

an image shows a series of brain scans arranged in a grid pattern

Childhood trauma rarely increases IQ—most studies have observed quite the opposite. However, that doesn’t mean those who experienced emotional trauma in early life are at a disadvantage in every possible way.

For example, trauma-exposed children can become more observant, vigilant, and aware of potential dangers. As a result, they may anticipate problems before they arise and implement preemptive solutions to ensure nothing goes amiss.

Of course, these advantages stem from their hyper-awareness of their surroundings and lack of trust in others, which aren’t necessarily good. Still, these specific cognitive skills can be quite helpful when navigating life and its challenges.

Can Childhood Trauma Cause Brain Damage?

Childhood trauma doesn’t necessarily cause brain damage, but it does affect the brain and its development, especially if it occurs in infancy. At this time, the brain develops rapidly, increasing in size and creating new neural pathways that are partly influenced by the environment.

So, if that environment is hostile, the brain’s development will reflect that. In particular, the hippocampus and prefrontal cortex, two brain regions crucial for cognition, may not function as well as they should.

For instance, the hippocampus, the area responsible for learning and memory, is typically significantly smaller in people with traumatic childhoods. That’s because the stress hormone cortisol interferes with its proper development.

Generally speaking, cortisol is quite useful—it improves alertness and prepares the body for dealing with danger and stress. However, it can overstay its welcome and change the brain’s structure, especially after exposure to trauma.

Cortisol delays the production of myelin, the fatty nerve coating responsible for insulating and improving communication between different parts of the brain. This means fewer new gray cells and less efficient communication in the hippocampus, an area that helps process information, among other things. This, ultimately, affects the volume and functionality of the hippocampus.

On the other hand, the prefrontal cortex, the region in charge of emotional regulation and decision-making, doesn’t experience significant structural changes.

Still, its function is significantly impaired due to the release of norepinephrine—another stress-related hormone that’s particularly elevated among patients with post-traumatic stress disorder (PTSD). As a result, these individuals have difficulty staying level-headed and may even develop some forms of psychotic disorders.

Normal Brain vs. Trauma Brain

The normal brain and the trauma brain can differ significantly, especially in terms of how they react to stress. In the following sections, we will examine the crucial distinctions between the two to gain a deeper understanding of how childhood trauma affects the brain.

Normal Brain

When the normal brain is exposed to a stressor, its first line of defense is the amygdala, a small part responsible for perceiving fear and danger.

The amygdala alerts the hypothalamus, the brain’s control center, which activates the adrenal glands. Then, they release epinephrine, better known as adrenaline, and prepare the body for fight-or-flight by increasing the heartbeat, expanding the airways, and sharpening the senses.

At the same time, the hypothalamus triggers the release of cortisol, which keeps the body in that high-alert state until the danger passes. Once it does, cortisol levels fall, and the body enters “rest and digest” mode.

Periods of relaxation promote brain health and the smooth functioning of all its parts. The hippocampus can focus on storing memories and emotional processing, while the prefrontal cortex regulates thoughts, actions, and emotions.

Trauma Brain

Similar processes occur in the trauma brain, except on a near-constant basis. In other words, people exposed to traumatic events have overactive amygdalas that perceive threats even when there are none.

As a result, the hypothalamus activates stress hormones much more frequently than necessary and keeps the body in fight-or-flight mode. This is rather taxing on the body and the brain, often resulting in physical and mental health issues.

Moreover, the trauma brain inhibits cognitive development, as it’s using all of its resources to stay on high alert. Consequently, adults and children with complex trauma may feel exhausted or burned out, though they seemingly have no reason to be.

Can Childhood Trauma Affect Your Memory?

Childhood trauma can affect memory due to its impact on the hippocampus. As mentioned before, this region of the brain is primarily responsible for encoding, organizing, and storing memories, as well as memory recall.

However, when a traumatic event occurs, the hippocampus doesn’t perform its function as well as it usually does under normal circumstances. This may result in unreliable memory coding or a partial or complete loss of specific memories.

So, although trauma is a highly distressing event that leaves permanent consequences on the psyche, people affected by it may not actually remember the details surrounding it. They may, for instance, struggle to recall the exact sequence of the events or lack any recollection of specific circumstances.

Considering that the brain enters a state of hyper-awareness when exposed to extreme stress, this may sound counterintuitive. However, it makes sense when we remember that the focus is on the danger itself and the feelings of fear—not details that may be non-essential for survival.

Aside from this specific effect on trauma-related memories, traumatized individuals can struggle with forming short-term memories and transferring them to long-term memory storage. This problem, caused by the decrease in hippocampal volume, may persist throughout their entire lives.

Can Early Intervention and Supportive Environments Help?

an image shows a group of people, including children and adults, standing together outdoors at sunset

Early intervention and supportive environments can help mitigate some of the worst effects of childhood trauma on IQ and cognition. Although its impact on mental development is significant, it doesn’t have to be a life sentence.

Thanks to its incredible neuroplasticity, the brain can change, adapt, and create new pathways at various stages of life—not only in childhood. That’s why we are able to pick up new skills, learn new information, or benefit from positive reinforcement and affirmative thoughts.

So, if trauma-exposed children are removed from the toxic environment and given proper support, encouragement, and care, their brains can heal to some extent. It may take time and lots of effort, but it isn’t impossible.

A study by Matte-Landry et al. provided significant evidence for this. According to their research, the more recent the trauma, the greater its impact on cognitive function. In other words, as children grow older and more distant from their trauma, their mental abilities will likely improve, even if they never reach the potential they could have had.

Ultimately, it’s important to pay particular attention to infants and identify potential risk factors in their environments. Unsafe neighborhoods, familial trauma, and low socioeconomic status can potentially lead to trauma, so children living in such circumstances should, at the very least, be given support and encouragement.

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Final Thoughts

The effect of childhood trauma on IQ is significant and profound, but that doesn’t mean there is no hope for improvement. On the contrary, early intervention and adequate community support can do wonders in minimizing the damage to both cognitive and mental health.

However, it’s also important to remember that the children who don’t have access to such a support system aren’t less capable than anyone else. Their brains may work differently, and they may struggle in certain areas, but ultimately, they can learn, grow, and live successful lives just like those who never experienced trauma.