One of the most common experiences among those who experience mental illness is that they believe they’re the only ones experiencing the stigma, symptoms, and challenges. Because the experience of depression or anxiety or bipolar is one that happens on the inside, it’s easy to draw the conclusion that no one else is experiencing the same thing.

Perhaps it would be easier if mental illness were something you could see on the faces of other people. Then, you’d be able to see that there are in fact others who are experiencing difficulty, just like you might be. When you can’t see the internal challenges of others, it’s easier to draw the conclusion that everyone else is fine and that you’re the only one with the problem.

However, numerous research studies confirm that there are a large number of teens who have a mental illness. There are a significant amount of adolescents who struggle with depression, anxiety, bipolar, substance abuse, and/or eating disorders. In fact, mental illness among teens is more prevalent than you might at first guess.

And this is the importance of understanding the prevalence of mental illness. First, if you are going through the challenges of mental illness yourself, then it’s incredibly helpful to know that there are others who are experiencing the same thing. Also, it’s helpful for clinicians and other experts in the field to know about how many teens are experiencing bipolar disorder, for example. If there are a large number of adolescents with bipolar within a particular region, it might point to understanding the disorder better. For example, in this case, perhaps there is an environmental contributor to the presence of bipolar disorder. Or perhaps there is a genetic contributor to bipolar disorder, which researchers have concluded that genetics does play a role in the presence of bipolar disorder.

Prevalence, according to the National Institute on Mental Health (NIMH), is defined as the amount of people or the segment of a population who has a specific characteristic over a given period of time. This definition sounds very scientific; however, essentially, it means the portion of a population who share a similar experience, such as those who are depressed or those who smoke. It’s rare that experts would know the exact number of people who have mental health characteristics, for the same reason mentioned above – mental illness is not something you can see necessarily. And for this reason, numbers are based upon what teens and adults report. In most cases, the prevalence of a particular disorder is estimated for a given population based upon the information that is already known.

According to NIMH, just over 20% of teens (ages 13-18), either currently or at some point during their life, have had a seriously debilitating mental disorder. This equates to about  1 in 5 adolescents. This statistic is a good example of prevalence – it indicates the number or percentage of a population, in this case adolescents, who have a mental illness. This statistic can be broken down further. For instance, 46.3% of 13 to 18 year olds have a life time prevalence of some form of mental illness. However, for severe mental illnesses, there are approximately 21.4% of 13 to 18 years olds who experience this type of disorder.

Severe mental illnesses are those that are considered to be more challenging and significantly impair a teen’s ability to function in their day to day life. These are illnesses such as schizophrenia, severe bipolar disorder, and severe depression.

One very common category of mental illness among teens are mood disorders. These are illnesses that affect emotions, feelings, and moods. For instance, depression is one type of mood disorder, often causing moods of low energy and sadness. There is a lifetime prevalence of 14% of 13 to 18 year olds who experience mood disorders. And 4.7% of teens experience a severe mood disorder, such as severe bipolar disorder.

Knowing about how many teens in a given population are experiencing what you might be experiencing can be helpful. It can be relieving to know that there are others out there just like you who are going through a similar experience. And what’s most useful is knowing that if someone else is going through it, perhaps he or she has found a way to manage symptoms, find treatment, and feel better! And this means you can too!