Is Global Developmental Delay the Same as Intellectual Disability?

What is Global Developmental Delay? Is Developmental Delay the Same as Intellectual Disability?

Many parents ask: Is developmental delay the same as intellectual disability?

In this article, we explain the connection between global developmental delay (GDD) and intellectual disability (ID), highlight their differences, and discuss how the NDIS can support your child’s development. Understanding the right diagnosis is crucial for accessing the best support.

What is Global Developmental Delay?

Global developmental delay (GDD) refers to children aged five years or younger who experience delays in achieving two or more developmental milestones. While children with GDD are at a higher risk of developing an intellectual disability later, GDD does not always lead to an intellectual disability.

Studies estimate that 1-3% of under five-year-olds ^[1] have GDD. However, having a GDD diagnosis does not necessarily mean a child will be diagnosed with an intellectual disability later in life.

Key Characteristics of Global Developmental Delay?

Significant delay in at least two developmental domains:

• Speech and language
• Motor skills
• Cognitive abilities
• Social and emotional skills
• Play skills.

Children with global developmental delays may appear younger than their peers in development.

Diagnosis typically occurs 6-12 months after initial concerns arise. Specialists such as a paediatrician or a psychologist usually confirm the diagnosis.

Early Intervention for GDD

The best outcomes occur when early intervention is provided, especially before the age of three, when a child’s brain is most adaptable. Therapies such as speech therapy, occupational therapy, and physiotherapy can significantly improve development.

What is Intellectual Disability

What is intellectual disability? An intellectual disability is diagnosed when a child has significant limitations in:

• intellectual functioning – learning, reasoning and problem-solving
• adaptive functioning – communication, social and practical skills.

Unlike GDD, an intellectual disability cannot be diagnosed until around age six, when cognitive testing becomes more reliable. Some children diagnosed with GDD later receive an intellectual disability diagnosis, but this is not always the case [2].

For more information, you can read the Children With Disabilities Australia Publication here.

How GDD and Intellectual Disability Differ

Factor	Global Developmental Delay (GDD)	Intellectual Disability (ID)
Age of Diagnosis	Before age 5	After age 6 (up to age 18)
Type of Delays	Developmental (motor, speech, cognition, etc.)	Cognitive and adaptive function
Progression	Some children catch up with intervention	Ongoing challenges in daily functioning

Can a Child Have Both GDD and Intellectual Disability?

Yes, a child can have both GDD and an intellectual disability. A diagnosis of GDD is often given while awaiting a more specific diagnosis. If a child continues to show severe developmental delays beyond early childhood, an intellectual disability diagnosis may follow.

Additionally, children with GDD or ID may also have other conditions such as:

• Autism Spectrum Disorder (ASD)
• Attention Deficit Hyperactivity Disorder (ADHD)
• Epilepsy

Getting the Right Diagnosis

Diagnostic Process:

• Detailed family and medical history
• Pregnancy and birth history
• Developmental and educational assessment
• Physical examination
• Genetic testing and brain imaging (if needed)

Why Diagnosis Matters:

• Helps families understand long-term challenges
• Ensures access to appropriate therapy and education support
• Provides clarity for future planning and interventions

How the NDIS Supports Children with Developmental Delays and Intellectual Disabilities

NDIS Support for Global Developmental Delay:

• Children with GDD under age nine may be eligible for early childhood supports (early childhood intervention) without a formal diagnosis [3].
• Supports may include:
  • Speech therapy
  • Occupational therapy
  • Physiotherapy
  • Positive Behaviour Support
  • Psychology
  • Early childhood supports

NDIS Support for Intellectual Disability:

• If a child’s diagnosis transitions from GDD to ID, they may qualify for NDIS disability support.
• The level of support depends on the severity of intellectual and adaptive functioning limitations.

Applying for NDIS? Click here for more information.

What Support Is Available?

Parents can access support through:

• Early childhood educators or schools
• Healthcare providers (paediatricians, psychologists)
• Allied health professionals (speech therapists, occupational therapists, key workers etc.)

Key Workers providing early childhood supports play an essential role in coordinating therapy and support services for children, ensuring consistent care and communication between professionals.

Find out more about the NDIS Developmental Delay and the Early Childhood Approach here.

Summary

• What is global developmental delay? It refers to a diagnosis given to children under five who fail to meet two or more developmental milestones.
• What is intellectual disability? It is a condition diagnosed in children over six with significant limitations in cognitive and adaptive functioning.
• Is developmental delay the same as intellectual disability? No, but GDD can sometimes indicate a future ID diagnosis.
• Early intervention is key! The earlier a child receives support, the better their developmental outcomes.
• The NDIS provides crucial support for children with developmental delays and intellectual disabilities, helping them access therapies and achieve their goals.

By understanding the differences between GDD and ID, families can ensure they receive the right diagnosis and support to help their child thrive.

References

[1] Access Paediatrics, 2017. Global Developmental Delay and Intellectual Disability.

[2] Vasudevan P, Suri M., 2017. A clinical approach to developmental delay and intellectual disability.

[3] NDIS, 2024. Developmental Delay and the Early Childhood Approach.