Introduction

Individuals with ASD and/or intellectual disabilities (ID) are at increased risk to engage in challenging behavior, which poses risks to self or others and is disruptive to functioning. This includes:

• Self-injurious behavior (SIB; e.g., head banging, skin picking, self-biting, and head hitting)
• Aggression towards others (e.g., hitting, kicking, biting, and scratching others)
• Pica (i.e., the ingestion of nonnutritive substances)
• Disruptive behavior (e.g., destroying property and throwing items)
• Elopement (i.e., leaving the presence of a caregiver outside of appropriate contexts), among others

Challenging behavior among individuals with ASD is multifaceted and presents as a heterogeneous phenomenon. Some individuals may present with only one form of challenging behavior (e.g., aggression), whereas others may engage in multiple forms (e.g., aggression, elopement, self-injury, pica). These challenging behaviors sometimes co-occur with irritability, generally defined as outbursts expressive of anger, frustration, and distress. Challenging behavior can be relatively mild and transient in some individuals, or highly severe, treatment resistant, and chronic in others. The pattern of occurrence can be episodic or near constant, and it can range from a few occurrences per week to hundreds of occurrences per day.