Signs of Undiagnosed Autism in Teenagers

Every teenager feels a little different in high school, but your gut might tell you otherwise. If you’ve noticed that your teen is struggling to make friends, obsessing over a specific topic, or having meltdowns when they become overwhelmed, these could be symptoms of autism.

In this article, we’ll discuss why autism is often overlooked in teenagers, what signs to look out for, and what you can do to create a more stable and supportive environment.

Why Autism is Sometimes Missed Until the Teen Years

Sometimes, children don’t receive an autism diagnosis until they are teenagers because they’re receiving other diagnoses. Most commonly, signs will point to attention-deficit hyperactivity disorder (ADHD) or a sensory processing issue. While these early diagnoses are not inaccurate, they often stop there.

Recent studies have shown that children diagnosed with ADHD early are 30 times more likely to receive an autism spectrum disorder (ASD) diagnosis after age six [*].

Autism symptoms also change as a child grows older. In younger children, autism might look like speech delays, an inability to maintain eye contact, and troubles with social interactions. Symptoms in teenagers, however, may be dismissed as regular social troubles.

In most cases, initial autism evaluations won’t always result in a diagnosis because specialists want to give the child time to develop. They may also favor the diagnosis with the best prognosis and focus on improving these symptoms first.

Diagnoses also experience gender disparities, with girls receiving a diagnosis later than boys, especially in the absence of intellectual disabilities [*].

Signs Your Teen Might Have Undiagnosed Autism

Symptoms of undiagnosed autism in teenagers can appear subtle and can be difficult to notice. Here are a few signs to note.

Social Communication Challenges

A teenager with undiagnosed autism will struggle significantly in social settings. Common social symptoms might include the following:

• Taking language very literally and struggling to comprehend jokes or sarcasm
• “Hijacking” conversations to focus on their niche interests
• Failing to understand social hierarchies and unspoken social rules
• Preferring to spend time by themselves or with others who share strictly the same interests
• Social masking by copying body language and slang, followed by long periods of extreme exhaustion
• Struggling to function within group dynamics

Executive Function Challenges

Many teenagers with undiagnosed autism don’t understand how the brain processes things. Because of this, they often encounter these executive function challenges:

• Becoming easily overwhelmed by big tasks or multi-step instructions
• Struggling to manage transitions (whether minor ones throughout the day or major life events)
• Forgetting important deadlines and schedules
• Experiencing time blindness, or being unable to gauge how much time a certain task will take
• Difficulties prioritizing tasks (whether at home or in an academic setting)
• Being physically and digitally disorganized (chaotic bedrooms, misplaced items, “messy” smartphone or tablet layout that makes it difficult to do homework or set reminders)

Sensory and Environmental Sensitivities

Teens with undiagnosed autism often experience their environment differently from others. In many cases, they may struggle with the following sensitivities:

• Auditory sensitivities: Difficulties drowning out background noise, extreme distress from loud noises, strong reaction to specific sounds (like chewing or scratching)
• Visual sensitivities: Becoming overwhelmed by bright lights or “loud” decorations, feeling overstimulated when exposed to messy environments
• Tactile sensitivities: Refusing to wear certain types of fabric, discomfort with physical touch, desiring certain types of pressure (weighted blankets or fluffy hoodies)
• Poor body awareness: Inability to comprehend internal states like hunger, sleepiness, or illness, being clumsy, or experiencing motion sickness

Rigid Routines and Intense Interest

A core component of autism is the focus on special interests. While parents and teachers might dismiss these special interests as obsession or stubbornness, they provide teenagers with joy and predictability. Here is how it might manifest:

• Demonstrates encyclopedic knowledge regarding a specific topic
• Needing to talk about this topic constantly, even when others are tired or disinterested
• Showing resistance to trying something new (clothes, food, places, etc)
• Needing fixed daily sequences with no changes to their schedule/routine
• Having a strict black-and-white interpretation of rules at home, school, and in social situations
• Using specific phrases and words repeatedly

The Impact of Undiagnosed Autism

Living with undiagnosed autism can be extremely challenging for teenagers and their parents. Because they lack the appropriate accommodations, teenagers might become more susceptible to mental health struggles. Individuals who don’t receive the appropriate autism diagnosis until adulthood have a markedly elevated likelihood of developing anxiety, depression, or a personality disorder [*].

Many teenagers are also often assigned inaccurate psychiatric labels, such as Borderline Personality Disorder (BPD), Generalized Anxiety Disorder (GAD), or Major Depressive Disorder (MDD). Because these diagnoses don’t equip the autistic teenager to understand their experiences, they often experience autistic burnout. When autistic teens are burned out, they might struggle to perform basic tasks and find themselves in a constant state of overwhelm.

Undiagnosed autism in teenagers also poses a unique safety risk, as they are more likely to experience abuse, neglect, and exploitation. Late-diagnosed teens are also likely to experience significant social struggles and escalating peer problems [*].

When to Consider a Professional Evaluation for Your Teen

Pursuing a professional evaluation for your teen can provide a helpful roadmap toward recovery. As academic and social demands increase, so does the need for regular support.

When undiagnosed teenagers spend all their time and energy masking as neurotypical, it can take a significant toll on their mental health. They may experience intense autistic meltdowns and shutdowns that require professional intervention.

Specific warning signs that require immediate intervention include suicidal thoughts, inability to function normally, becoming completely socially withdrawn, or having extreme reactions to sensory triggers.

Available Treatment and Support

There is no cure for autism, but early intervention can significantly improve a teenager’s academic performance and social skills. Treatments aim to reduce symptoms that interfere with daily functioning and take various approaches.

For example, behavioral treatment focuses on changing unwanted behaviors, such as meltdowns and aggression. Most commonly, teens may undergo applied behavioral analysis (ABA), which encourages positive behaviors and discourages harmful ones by rewarding good habits and ignoring bad ones. This particular treatment is effective for improving socialization, communication, and expressive language [*].

Developmental therapies focus on improving certain skills, such as speech and language. Other developmental approaches include occupational therapy, which helps teenagers function more independently.

In an educational setting, a primary accommodation is the Treatment and Education of Autistic Related Communication-Handicapped Children (TEACHH), which equips educators with more structured teaching methods. It provides clear boundaries for organizing classrooms to reduce distractions, integrates visual schedules for predictable routines, and dictates work systems that encourage independence.

In more extreme cases, specialists may prescribe medication to treat co-occurring symptoms, such as self-harming behavior or an inability to focus. Medications may also be used to manage other conditions, such as depression and anxiety.

The Bottom Line

Autism can be challenging to diagnose, especially when symptoms overlap with other mental health conditions. If you suspect that your teenager may be autistic, it’s best to take them to a mental health specialist.

Use our social skills worksheets to help your child better understand social cues, and our feelings worksheets to teach your child to be more in tune with their emotions.

Sources:

1. Miodovnik A, Harstad E, Sideridis G, Huntington N. “Timing of the Diagnosis of Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder.” Pediatrics, 2015.
2. Bargiela S, Steward R, Mandy W. “The Experiences of Late-diagnosed Women with Autism Spectrum Conditions: An Investigation of the Female Autism Phenotype.” Journal of Autism and Developmental Disorders, 2016.
3. Jadav N, Bal VH. “Associations between co‐occurring conditions and age of autism diagnosis: Implications for mental health training and adult autism research.” Autism Research, 2022.
4. Mandy W, Midouhas E, Hosozawa M, Cable N, Sacker A, Flouri E. “Mental health and social difficulties of late‐diagnosed autistic children, across childhood and adolescence.” Journal of Child Psychology and Psychiatry, 2022.
5. Yu Q, Li E, Li L, Liang W. “Efficacy of Interventions Based on Applied Behavior Analysis for Autism Spectrum Disorder: A Meta-Analysis.” Psychiatry Investigation, 2020.