There are heaps of different things that can support healthy brain development during adolescence (ages 12–18), but there are also some things that might not be so good for our brains. In this paper, we will talk about why sports are good for the brain during adolescence, because they not only offer some protection against the development of mood disorders but can also help people who have mood disorders to feel better. But we will also talk about how getting a concussion while playing a sport might put someone at risk of developing a mood disorder later in life.

Mood Disorders in Adolescents

Mood disorders, such as depression and anxiety, are big mental health problems for young people all over the world. Having a mood disorder can make it difficult for a young person to develop positive relationships with friends and family, concentrate at school, or feel hopeful about the future. When someone feels these kinds of things over weeks or even months, that person may begin to experience depression (feeling really low and empty) or have thoughts of suicide (not wanting to live any more). Mood disorders, such as depression and anxiety play a part in the development of suicidal thoughts and behaviors (also called suicidality). It is really important that we look for ways to prevent the development of mood disorders and also ways to help young people who have mood disorders to feel better.

The brain goes through a lot of changes during adolescence. In regard to mental health in young people, these changes can make the brain quite sensitive to injuries. Let us start by talking about how the various areas of the brain are connected to each other. Regions of the brain need to communicate with each other so that we can think, plan, and carry out tasks in everyday life. The brain is made up of gray matter and white matter. Gray matter contains the cell bodies of neurons (which are the building blocks of the brain that process information). White matter consists of parts of neurons called axons, which are the connections that link different regions of gray matter together (see Figure 1). During adolescence, the white matter begins to decide which brain areas need to be connected the most. Think of this like a road map. Big cities get visited by more people more often, so highways are built to make sure that people can access these places quickly and easily. On the other hand, little country towns might only have dirt tracks connecting them, because they do not get visited as often. In the same way, as the brain develops throughout adolescence, it prioritizes building the white matter connections that we use the most and removes those that we do not use anymore (see Figure 2; [1]). This allows the brain to quickly respond to certain, common things without you having to think about them too much.

During adolescence, the prefrontal cortex (PFC) and the limbic system are two regions of the brain that are under major construction (see Figure 3). The PFC is involved in making decisions and in goal-directed behavior (thinking about what you want to do, how to do it, and then doing it). The limbic system controls our feelings, memories, and stimulation (which allows us to explore, learn, and discover interesting things). Research has found that young people who experience mental health issues like suicidality, anxiety, and depression during adolescence are at risk of their white matter highways failing to connect these important regions of the brain properly [2]. If the connections between the PFC and the limbic system are not healthy and strong, it is more difficult for someone to solve problems, set goals, and manage emotions in a healthy way. When they cannot do these important tasks, people can begin to feel sad, stressed, and overwhelmed. Unfortunately, these kinds of difficulties place young people at risk of developing a mental illness.

Sports Are Good for the Developing Brain

There are lots of different ways we can help support healthy brain development throughout adolescence. One of these is physical activity. Through its effect on how we think and feel, as well as its effect on the way our brains form, physical activity has been shown to significantly benefit adolescent mental health and development. How does this happen? Research has shown that physical activity improves brain development during adolescence through its positive effect on neurogenesis (the growth of neurons) and brain plasticity (the ability for the brain to change and adapt to new and different things) [3]. Playing a team sport can offer even more protection and developmental perks than just physical activity alone! Participating in a team sport exposes a person to both the benefits of physical activity on the brain, as well as to great social support and engagement with other people.

By participating in team sports, adolescents are more protected against mood disorders, because they feel more involved with their friends, they feel better about themselves and their skills, and they feel more confident in social settings [4]. This is exactly what we want to see, because young people who have strong relationships with their friends and family have been shown to be more resilient, hopeful, and positive about their lives, which is basically the opposite of having depression or thoughts of suicide. These effects of team sports can help the brain make strong, positive connections and provide lasting benefits to a young person’s mental health.

Concussion and Mood

Unfortunately, because many team sports involve a lot of people moving quickly, there is a risk that players might get injured. Concussion is an injury to the brain that occurs when someone is hit in the head or body, causing the brain to be thrust forwards or backwards in the skull, which disrupts normal brain function. Concussions can feel and look different in different people. Some people with concussions might become forgetful, others might become grumpy or depressed; others might get a really bad headache or feel like they are going to be sick. Some people might even experience a combination of these different symptoms. Young athletes might feel these symptoms straight away or it might take hours or even days for the symptoms to emerge. If you think you have a concussion, you should visit your doctor to get checked out, just to be on the safe side. Most people will recover from a concussion in about 2 weeks without any ongoing symptoms or major disruptions to their brain development. However, there are some people who, following a concussion, continue to have problems with things like memory and emotions. This may be because of injury to the parts of the brain that control these functions.

The brain regions that have been shown to be most impacted by concussions include the PFC and the limbic regions of the brain. These are the same regions of the brain that are under a lot of construction during adolescent development, and the same regions that are involved in mood disorders like depression and suicidality. This might be why concussions and depression share so many symptoms (see Figure 4). The damage a concussion can do might actually place a young person at risk of developing a mood disorder later in life, because it impacts the same brain regions that are rewiring and developing during adolescence. In fact, adolescents with a history of concussion have been found to be over 3 times more likely to experience depression in their lifetime, compared with young people who have never had a concussion [5]. Research looking at depression and suicide in adult and retired athletes has begun to show us that concussion may undo a lot of the good things that sports do for the brain. For example, concussions have been linked with neurodegeneration (the early death of neurons), reduced brain plasticity, and the development of depression and suicidality [6]. Unfortunately, we do not yet know what the long-term emotional and developmental consequences are for young people who get a concussion.

To Play, Or Not to Play?

A lot of research still needs to be done to improve our understanding of the interactions between participation in team sports, concussion risk, and long-term mental health outcomes for adolescents. Most of the research we have on concussions and how they relate to the development of depression and other mood disorders has not been looked at in adolescents. This makes it difficult to totally understand the long-term impact of concussions on youth mental health. As we have said, adolescence is a sensitive time in the development of the brain. We need to make sure we are doing everything we can to support happy, healthy development throughout this period, which includes being physically active with friends!

Glossary

Adolescence: ↑ The stage of development between childhood and young adulthood, typically between 12 and 18 years of age.

Mood disorders: ↑ A psychological disorder in which a person’s feelings and emotions remain either too active (such as anxiety) or not active enough (such as depression) over several weeks.

Concussion: ↑ An injury to the brain that occurs when someone is hit in the head or body, causing the brain to be thrust forwards or backwards in the skull, which disrupts normal brain function.

Neurogenesis: ↑ The growth of neurons. The opposite of this is neurodegeneration, which is the death of neurons.

Brain plasticity: ↑ Our brain’s ability to change and adapt to new and different things.

Conflict of Interest Statement

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.