Developmental Disabilities

Developmental disability (also known as neurodevelopmental disability) is an umbrella term that includes a diverse range of diagnoses which arise from an impairment of the central nervous system.

Specialist Behaviour Support Services and Speech Pathology

Female speech therapist helping a little girl with speech therapy - an example of a developmental disability

Definition of Developmental Disabilities

Developmental disability (also known as neurodevelopmental disability) is an umbrella term that includes a diverse range of diagnoses which arise from an impairment of the central nervous system. This means there are differences in brain development, structures and functioning.

Types of Developmental Disabilities

The Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-V) (American Psychiatric Association, 2013), is a handbook that is used by professionals around the world to diagnose mental disorders. The DSM–V lists the various types:

Intellectual Disabilities:

Communication Disorders:

  • Language Disorder
  • Speech Sound Disorder (previously Phonological Disorder)
  • Childhood-Onset Fluency Disorder (Stuttering)
  • Social (Pragmatic) Communication Disorder
  • Unspecified Communication Disorder

Autism Spectrum Disorder

Attention-Deficit/Hyperactivity Disorder

Foetal Alcohol Spectrum Disorder


Specific Learning Disorder

This is a neurodevelopmental disorder that begins during school-age, although may not be recognised until adulthood. For example, dyslexia, dysgraphia and dyscalculia. These disorders can have a range of impacts. For example, difficulties with putting thoughts into written words, spelling, reading comprehension, math calculation and math problem solving. Difficulties with these skills may cause problems in learning subjects such as history, math, science and social studies and may impact everyday activities.

Motor Disorders

  • Cerebral Palsy
  • Developmental Coordination Disorder
  • Stereotypic Movement Disorder
  • Tic Disorders
  • Tourette’s Disorder
  • Persistent (Chronic) Motor or Vocal Tic Disorder
  • Provisional Tic Disorder
  • Other Specified Tic Disorder
  • Unspecified Tic Disorder

Unspecified Neurodevelopmental Disorder (UNDD)

UNDD is a diagnosis given to persons experiencing symptoms of a neurodevelopmental disorder, but the symptoms don’t meet the full criteria for one of the Neurodevelopmental disorders. Symptoms of UNDD could include:

  • Failure to reach expected developmental milestones for walking and speech.
  • Inability to interact appropriately with peers.
  • Poor academic performance.
  • Overreaction to frustration compared to peers.
  • Emotionally labile in comparison to peers.

Causes of Developmental Disabilities

These disorders are developmental in the sense that delays, disorders, or impairments are severe and last throughout a person’s lifetime. The conditions are a result of a complex mix of factors that may or may not be identifiable. The causes include:

  • Before birth related factors such as: genetics; parental health (e.g. infections and diseases the mother might have had during pregnancy); parental behaviours (e.g. smoking, drinking and drug taking during pregnancy) and exposure to high levels of environmental toxins (e.g. lead, mercury).
  • Around birth related factors such as low birth weight, prematurity and obstetric complications.
  • After birth related factors such as exposure to infections, diseases, malnutrition and injury experienced any time before the age of 18 years.

Symptoms of Developmental Disabilities

Having a developmental disability impacts skills within these areas: 

  • Communication
  • Cognitive development
  • Motor
  • Self-direction
  • Self-care
  • Independent living
  • Economic self-sufficiency

Depending on the disorder, type, and degree of disability, the individual has the symptoms will vary in how it presents in each developmental area.

Our blog article 'Communication Strategies for People with Profound and Multiple Learning Difficulties' discusses a range of practical strategies you can use to develop and strengthen communication skills in individuals with Developmental Disabilities.


American Psychiatric Association (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.).


Behaviour Help

If you are supporting an individual with this diagnosis, please refer to our services and resources. They aim to help children, adolescents and adults achieve better communication, social, emotional, behavioural and learning outcomes. So whether you are wanting guidance on parenting, teaching, supporting or providing therapy, Behaviour Help is at hand.

Note: This is not an exhaustive list of all the possible causes, symptoms and types but some general information that can be further explored. Based on what you have read if you have any concerns about an individual, please raise them with the individual/s. The caregiver can then raise these concerns with their local doctor who can provide a referral to the relevant professional (e.g. paediatrician, psychologist, psychiatrist, allied health professional and learning specialists) for diagnosis and treatment if appropriate.

Ask Dolly

Since you’re here, you probably have questions and concerns. I am Dolly Bhargava, am here to help. I am a NDIS registered behaviour support practitioner and speech pathologist.

I have worked in a number of settings for over 21 years so, how can I help?

Please tell me what is worrying you right now and I will do my best to recommend resources and/or services that will be most useful to you in your situation.

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