Why Do Some Children Get Anxiety Disorders?

Everybody is scared from time to time. Some children are scared of spiders, some fear snakes, and others are nervous about saying something in front of the class. Some children are so anxious they cannot go outside or go to school. This extreme level of anxiety is called an anxiety disorder [1].

We want to know why some children develop anxiety disorders and others do not. This will help us prevent children from getting anxiety disorders. Studies have shown that some toddlers avoid new situations a lot more than others do. For example, some toddlers stay very close to their mothers if somebody enters the room, and they will not play with unfamiliar toys. These toddlers are called avoidant, and they are more likely than others to be anxious when they are older [2]. But not all avoidant toddlers will become anxious when they grow up. So, we wanted to find out why some of these avoidant toddlers become anxious.

Does The Brain Play A Role?

To learn why some avoidant toddlers become anxious, we studied their brains [3]. We wanted to know if the activity of the brain can predict which avoidant toddlers are more likely to become anxious as preteens. We measured brain activity in two situations: while the preteens were resting and while they were making mistakes. To measure brain activity during rest, preteens just had to sit still and do nothing. To measure brain activity when they were making mistakes, the preteens were asked to do a difficult task very quickly. Usually, your brain gives a “warning signal” when you make a mistake. This signal is even bigger if somebody else sees your mistake [4]. We wanted to know if brain activity during rest and during mistakes could show which preteens have become very anxious.

In our study, we asked two research questions. First, does the brain activity of preteens during rest show us which avoidant toddlers have become very anxious? Our hypothesis was that brain waves at rest will show which avoidant toddlers will become very anxious as preteens. Second, does the brain’s response to making mistakes in front of somebody else show which avoidant toddlers have become very anxious as preteens? Our hypothesis here was that avoidant toddlers who have bigger warning signals when making mistakes in front of somebody else as preteens will be more anxious than those with smaller warning signals.

How Did We Study The Role Of The Brain In Anxiety?

To study whether the brain can show which avoidant toddlers become very anxious as preteens, we needed to wait until they grew up. After they became preteens, we could look at how their brains might be different. This is called longitudinal research: we studied the same children several times over 10 years. Children first came to the University of Maryland when they were 2 and 3 years old. Then, they came back when they were 13 years old!

We looked at how 268 toddlers (2–3 years old) behaved in three new situations (Figure 1). In the first situation, they were in a room with a grown-up stranger. In the second situation, they were given a loud robot toy. In the third situation, they were near a dark and mysterious tunnel. All these situations could be scary for a toddler. We wanted to put them in scary situations to see how they reacted. Some toddlers took longer to go to these new and scary things. Some toddlers stayed close to their parents. Others played with the robot right away. We used these situations to see which toddlers were more avoidant.

Some of the same children came back when they were 13 years old. During this visit, 123 preteens filled out a questionnaire about how anxious they are in different situations. Their parents filled out the same questionnaire about their children [6]. We also studied the children’s brain activity using an electroencephalogram (EEG), which is a recording of the electrical activity of the brain. Brain activity consists of little bursts of electricity that happen when the brain is doing something. These bursts of electrical activity can be big or small, and fast or slow, depending on what the brain is doing. To record brain activity with an EEG, the preteens wore a cap with sensors while they either rested or performed a task on the computer.

We first measured brain activity during rest, when the preteens were sitting still and doing nothing. An experimenter in the room asked the preteens to keep their eyes closed for 30 s and then open their eyes for 30 s. This happened 6 times in total. Then, we measured brain activity when the preteens were making mistakes. To make sure the preteens would make mistakes, they all played the same computer task called the social flanker task [4]. During this task, the preteens saw 5 arrows on a screen and had to indicate whether the middle arrow pointed to the left or right (Figure 2A). Sometimes, the middle arrow was different from the arrows around it, which made the task difficult and caused preteens to make mistakes—that is exactly what we wanted! If the preteens did not make enough mistakes, the computer asked them to go faster, to make sure that they made some mistakes.

As you can see in Figure 2, there were two versions of the task: a social condition and an alone condition. During the social condition, preteens were told that another preteen would watch and evaluate them through a webcam. In reality, nobody was watching them! During the alone condition, the preteens received feedback from the computer instead of an imaginary preteen. We wanted to see if preteens would react differently to mistakes if there was somebody watching them.

What Did We Find?

To remind you of our research question, we wanted to know if brain activity could tell us which avoidant toddlers actually become more anxious as preteens. If brain activity can tell us something about anxiety, we can use this information to help find and treat preteens who struggle with anxiety.

First of all, we found that brain activity when preteens were at rest did not tell us which of the avoidant toddlers were more anxious as preteens [7]. However, when preteens made mistakes, their brains responded with a “warning signal.” This signal was bigger when they thought that they were being watched by somebody else. Preteens who showed this bigger warning signal when being watched and who were avoidant as toddlers were more anxious than those with smaller warning signals [8].

Summary

In our study, we wanted to know why some children develop anxiety disorders. We also wanted to find out if the brain plays a role. Some toddlers avoid new situations, for example, they do not want to play with a new and noisy toy. Some want to stay close to their mothers if a stranger comes into the room. These avoidant toddlers have a greater risk of developing an anxiety disorder later in life, compared to toddlers that do not avoid new things. We wanted to figure out why only some avoidant toddlers become more anxious as they grow up. To answer this question, we studied how their brains responded to various situations.

We now know that brain activity when a preteen is at rest does not show which avoidant toddlers have become very anxious as preteens. Before our study, we thought that resting brain activity would help us to predict anxiety. Even though our initial prediction was wrong, this finding is still important because it will help other scientists who might think of the same question when they try to help anxious kids. Now, those scientists can ask new questions about anxiety in the brain. We also learned that avoidant toddlers whose brains had a bigger warning signal as preteens were more likely to be anxious. This finding gave us an idea of which toddlers might develop anxiety. If we know which toddlers are more likely to be anxious, we might be able to help those kids before their anxiety becomes too severe.

Studying the brain and behavior can help us to understand why some children develop anxiety while other children do not. As we learn more about the brain, we can come up with new ways to help children feel less anxious. We want to find new ways to help anxious children, so that every child can feel happy, even when they are in new or scary situations.

Funding

This work was supported by the National Institute of Mental Health, USA (R37HD17899 and U01MH093349) to NAF and the Intramural Research Program at the National Institute of Mental Health, USA (ZIAMH002782 and NCT00018057) to DSP.

Glossary

Anxiety: ↑ An overwhelming sense of worry, uneasiness, or fear (for example, of spiders, snakes, or public speaking). Sometimes anxiety is felt in the body as tension, sweating, or increased heart rate.

Anxiety Disorder: ↑ Anxiety so severe that it disrupts daily life. Children with anxiety disorders may not be able to go to school or leave their homes because they are too scared.

Avoidant: ↑ Moving or turning away from something. Avoidant toddlers do not want to play with new toys or do not want to approach a stranger that enters the room.

Longitudinal Research: ↑ A study that gathers information about an individual or a group multiple times over a long period.

Electro-encephalogram (EEG): ↑ A recording of the electrical activity of the brain. It is recorded using a cap with sensors that is worn on the head.

Social Flanker Task: ↑ Computer task in which preteens indicate the direction of an arrow. In the social condition, they thought they were being watched by another preteen–but this was not the case.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.