Behavior and Fragile X Syndrome

When discussing Fragile X syndrome and behavior, it is important to note that — like every person — the focus should be on the individual. Many behaviors are positive, and it is those behaviors you will see most often in addition to challenging behaviors. Behavior problems serve a purpose (or a function) and are often a form of communication. Addressing behavioral challenges in an individual with FXS should start with a comprehensive evaluation. A proactive approach with appropriate supports and accommodations will likely foster positive outcomes and set up the individual with FXS to succeed in their home, school, or community.

Treatment & Interventions

  • Strategies for Addressing Aggressive Behavioral Outbursts in Adolescents and Adults with Fragile X Syndrome
  • Behavioral Challenges in Fragile X Syndrome
  • Sensory Processing and Integration Issues in Fragile X Syndrome
  • Hyperarousal in Fragile X Syndrome

Info Series

  • Fragile X Info Series: Your In-Person Visit to a Fragile X Clinic


From Our Blog

More Resources

Treatment & Interventions

This document provides strategies for addressing aggressive behavioral outbursts in adolescents and adults with Fragile X Syndrome, including possible causes of aggression and ways to minimize and prevent aggressive behavior.

Links to Language in Fragile X Syndrome treatment recommendations.

This document provides information about what language development may look like for individuals with FXS. We discuss receptive language (what is understood), expressive language (how an individual communicates), pragmatics (how language is used), and speech (how sounds and words are produced).

Links to Behavioral Challenges in Fragile X Syndrome treatment recommendations.

This document notes commonalities in behavior challenges in Fragile X syndrome, including intensity, frequency, and duration. These behaviors are influenced by other factors, such as their environment and medical conditions, and it is critical to address behavioral concerns, including eating and feeding, with an individualized approach.

Link to Sensory Processing and Integration Issues in Fragile X Syndrome PDF.

When possible, parents should be proactive in preparing their children for daily challenges. Learning to live within the bounds of sensory integrative and sensory processing issues may mean limiting exposure to too much intensity until a child can manage these situations. Learn more about treatments for sensory integration issues.

Link to Hyperarousal in Fragile X Syndrome.

When problem behaviors occur, it is important to recognize that they may be caused by hyperarousal and to first try to identify any sources that may be overstimulating the person. The initial intervention should always be to try to reduce environmental stimulation. When that is not possible, it may be advisable to remove the person from the overstimulating environment. Learn more about treatments.

From Our Info Series

You may also want to browse our other available Info Series topics, each of which is available to read online or download and print on your home or office printer. All Info Series PDFs are available in English and Spanish versions.

Fragile X Info Series: Your In-Person Visit to a Fragile X Clinic.

A summary guide, checklists, and resources on how to prepare a child or adult for their first visit to a clinic.


  • Dr. Lauren Schmitt is a licensed clinical psychologist with extensive training in cognitive functioning in individuals with neurodevelopmental disorders.

How Many Times Is He Going to Ask That? Perseverative Questioning and Other Behavioral Inflexibility in FXS — Presentation

By |Jul 16, 2022|

Dr. Lauren Schmitt, a licensed clinical psychologist with extensive training in cognitive functioning in individuals with neurodevelopmental disorders, discusses how behavioral inflexibility is likened to being stuck — a state in which the individual is unable to move on from a current behavior or thought.

  • Child stacking Legos while playing on the floor.

My Child is Home… Now What?? Play Skills

By |Apr 7, 2020|

In this webinar, Rebecca Shaffer guides us through some pointers about how to build play skills while your children are at home, and some great resources for thinking through different play opportunities while they’re at home.

From Our Blog

Home for the Holidays: Making the Visit Comfortable

By |Dec 19, 2022|

A reader asks (and we answer): I heard it can be challenging for individuals with Fragile X to meet new people and be in new situations. Do you have any tips on making the children feel comfortable?

  • Young boy seated in an airplane with seatbelt

Tips for Flying on an Airplane

By |Jun 30, 2021|

Traveling with your young or adult child with Fragile X syndrome on an airplane can be very stressful for both of you. These tips are provided by parents based on their experiences with their own children. Find what works for you, your child, and your family.

  • Boy hiding under cushions on a sofa

When Disappearing Acts Are a Good Thing

By |Apr 2, 2020|

Behavior can often be misunderstood and punished because the parent or caregiver doesn’t recognize its function for the child. Caregivers must look behind the behavior to learn what they’re trying to communicate.

  • Visualize the word explore

Managing Anxiety … What Works And Why?

By |Dec 6, 2018|

Most children who come to see me have a combination of developmental delays, communication challenges and symptoms of anxiety, resulting in frequent tantrums. It is common for parents to share details about their daily struggles.

  • Sensory diagram.

Concept and Use of a Sensory Diet

By |Sep 21, 2018|

Leading pediatric occupational therapists, Tracy Stackhouse and Sarah Scharfenaker, provide an overview of the concept and use of sensory diet including a downloadable sensory diet template, and an example of a completed template for a sample patient.

  • A toddler wearing diapers laying on his back with his arms across his face, having a tantrum.

10 Rules of Time-Out

By |Sep 14, 2017|

I have found these 10 time-out “rules” to be the keys to success. They are based on the fundamental principles and incorporate adaptations for children with Fragile X syndrome by accommodating repetition, consistency, and predictability.

  • Ian, who has Fragile X syndrome, laying back in the dentist's chair while the dentist works on his teeth.

Visiting the Dentist

By |May 10, 2017|

I learned pretty quickly that visits to a dentist were going to be a challenge for my son, Ian. I demonstrated the process over and over again. I helped him brush his teeth, encouraged him to brush his own teeth, tried different toothbrushes and toothpaste. I needed Bonnie.

Verbal Perseveration! Verbal Perseveration!

By |Mar 22, 2017|

Let's discuss verbal perseveration (VP), a very typical and pervasive aspect of language in Fragile X syndrome. Does VP interfere with daily living and activities? You bet your boots it can!

  • A mother holding her toddler son in her arms while he points excitedly to an unknown object.

Video Modeling

By |Nov 9, 2016|

Therapy is a fun, creative process – one of the reasons that we have been at this for so long! One of the challenges of being a therapist is staying on top of the ever-emerging intervention techniques that come into our practice and making them work for individuals with FXS.

Visual Wizardry: Using Visual Supports to Change your Child’s Life

By |Aug 31, 2016|

Visual supports help translate the environment and expectations to an individual with FXS without requiring direct processing of language. This type of information can be processed quickly. Visual supports remain present, so they can be referred to more than one time, whereas verbal directions might be heard and then forgotten. Learning to use visual supports can help alleviate anxiety for the person with FXS and frustration for the person providing support.

  • Chart for a child to track progress toward a goal.

Oppositional or Merely Anxious?

By |Aug 8, 2016|

Children with and without Fragile X syndrome learn to maneuver their environments in order to survive and thrive. In order to discern whether a behavior is oppositional, or merely a reaction to anxiety, pay attention to your reaction.

  • A young boy with Fragile X syndrome playing in a sandbox.

Teaching Your Child to Ask for Something

By |Jul 30, 2015|

One of the most challenging things for my son, Ian, to do is ask another person (not mom or dad) for something — like a favor or request — in an appropriate way. This [...]

  • A child without a face placing their hands over their ears.

Behavior and Fragile X Syndrome

By |Jun 3, 2015|

When discussing FXS and behavior, the focus should be on the whole person. Some behaviors may be a result of the condition, of which many are positive.

  • Mouse and Tracy

My Child Won’t Answer Questions!

By |Jul 29, 2013|

Direct questions are typically the way we try to engage people in conversation. For children with FXS, we need to learn other strategies. It is critical to understand why it is so difficult for children with FXS to understand and respond to these questions, before we get to the how of getting answers.


Stopping the Stuffing — Therapy Programs for You and Your Child
If you’re the parent of a child with Fragile X syndrome, you’re probably very familiar with mouth stuffing. Mouth stuffing for kids with FXS is usually an adaptive means of trying to succeed with eating.

Common Feeding Difficulties and How to Make Mealtime More Successful for Your Fragile X Family
Kristin Burgess Watson highlights some common feeding difficulties ranging from over-stuffing to picky eating that individuals with Fragile X struggle with and suggests some strategies to make mealtime more successful for your family.

Oral Sensory Seeking – Why is my Child Still Putting Things in Their Mouth? — Griffin Occupational Therapy
This post explores oral sensory-seeking behaviors and reasons why older children might continue to put things in their mouths.

Sensory Issues and Feeding — FeedingPlus
Nicola Pratt (SLP and feeding therapist) explains sensory issues and how they impact kids’ feeding and contribute to picky eating.