Autism Spectrum Disorder: Symptoms and Causes

Autism spectrum disorder is a condition that affects one out of every 68 children and teenagers in the USA. While most people with autism are diagnosed during early childhood, sometimes those who are highly functional aren’t diagnosed until the teen or adult years, if at all. Those who are diagnosed during childhood might experience changes in the way they behave as they go through their teen years and beyond. Read on to learn more about autism spectrum disorder, namely its causes and its symptoms.

What Causes Autism?

The short answer is that there’s not one definitive cause of autism. There are several factors that might contribute to an increased risk of developing the disorder, but most children who have these factors do not develop autism, and many individuals who do have autism don’t have any of the risk factors. Some of the possible factors include:

  • A family history of autism. There could be a genetic component in some families and parents might carry genes that could predispose a child to autism even if they don’t have the condition themselves.
  • Pregnancy complications, including prematurity.
  • Advanced parental age. There is some evidence that the older the parents are, the more likely their child is to develop autism.
  • Closely spaced pregnancies. Having one child and then having another less than a year later could put the second-born child at a higher risk of developing autism spectrum disorder.

It’s important to keep in mind that plenty of children who have a familial history of autism, who were born prematurely, whose parents are older than average, and who were born less than a year after their older sibling do not develop autism. Conversely, there are children and teens who have no family history, were born at term to parents in their 20s, and who have no siblings close in age that do develop autism.

One factor that does not make a child more or less likely to develop autism is vaccination status. Although there have been widely debunked theories concerning vaccines as a contributor to ASD, all of these have been disproven. Autism affects populations that do not vaccinate children. Although symptoms often crop up around 12 to 18 months of age (when some vaccines, including the MMR, are given), the disorder is not linked to the vaccines.

It’s also important to understand that one major reason for autism spectrum disorder diagnoses to be more prevalent now than ever before is that the definitions of the disorder have been widened and awareness is at an all-time high level. Children and teens who might have been labeled as “learning disabled” or “quirky” in decades past might now be diagnosed as being on the autism spectrum.

Symptoms of Autism in Teenagers

A teen with autism will often have trouble communicating with and relating to others. If the condition isn’t diagnosed before the teen years, it’s likely that the teen is on the high-functioning end of the spectrum; they might have a mild case of pervasive developmental disorder or they might have Asperger’s syndrome. In general, they will have managed to get through elementary and middle school and might not have had severe symptoms that led teachers, parents, and their pediatrician to know right away that something was amiss.

Some symptoms that teens with autism might have include:

  • Difficulty relating to peers and adults because they don’t read non-verbal cues such as body language or tone of voice.
  • Taking statements literally. A teen with ASD might not understand sarcasm, for example.
  • Aggression and frustration. Older children and teenagers with autism often know that they are not able to relate and communicate the same way that others their age do.
  • Excessive talking about one topic that they are very interested in despite others around them not showing any interest; they don’t recognize the social cues to allow the subject to be changed.
  • Emotional outbursts when conditions change unexpectedly or when a routine is disrupted.

If your teen has these symptoms and hasn’t been evaluated for autism spectrum disorder, seek out the advice of his or her pediatrician. They can refer you both to a specialist who can do the evaluation.

Treating Autism in Teenagers

A teen who was diagnosed earlier in childhood will usually continue with the same therapies that they’ve had all along with tweaks and changes as needed. For a teen who is diagnosed in later childhood or during adolescence, here are some of the ways that they might be treated:

Medication. Some teens with autism are prescribed medication to help with some of the symptoms they might be having. For example, an individual who has depression, anxiety, or ADHD symptoms as part of their disorder might benefit from medications used to reduce those symptoms. These medications are usually used in conjunction with behavioral therapies, however; medication on its own will not be enough to help someone with autism reach their full potential.

Applied behavioral analysis (ABA). This is a type of therapy that includes an antecedent, or command; the behavior of the teen; and a consequence. The consequence might be something positive, such as a piece of candy, or neutral, such as no response at all

Relationship development intervention (RDI). This therapy focuses on learning how to have spontaneous relationships with others. With ABA, a specific outcome or behavior is sought, but with RDI, it’s more about teaching the skills of flexible thinking, social coordination, and solving problems that have no clear right or wrong approach

Occupational therapy (OT). Occupational therapy can help teens who are struggling with sensory overload and other issues. Some of the techniques used can be physical therapy, sensory integration, and sound therapy.

The specific types of therapy that your teen has depends on his or her symptoms. Talk to a specialist about what will help your teen develop long-term skills and strategies for a functional adulthood.

Commonly Asked Questions

Can Autism Be Developed Later in Life?

A majority of autism cases are diagnosed during early childhood. However, mild cases that may have gone undetected in adolescence can be diagnosed in high-functioning autistic teens and adults.

Are There Early Signs That Suggest My Child Has Autism?

Some of the early signs of autism that adolescents will display include difficulty making connections to peers, struggling to understand sarcasm, and sensitivity to changing environments.

Is Autism Treatable for Adolescents?

Autism is highly treatable. A few examples of treatment options include applied behavior analysis therapy, relationship development intervention therapy, occupational therapy, and medication supportive to therapies.


Autism is common enough that chances are good there are other adolescents in your teen’s circle of acquaintance who have it. Not all people with autism have the same symptoms, so it’s important not to jump to conclusions about how your teen will continue to grow and develop. Talk to your teen’s doctor if you have concerns.