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Severity of Learning Disabilities


• Mild learning disabilities indicates an IQ = 50-70, or mental age of 9-12 years
• Moderate learning disabilities indicates an IQ = 35-49, or mental age of 6-9 years
• Severe learning disabilities indicates an IQ = 20-34, or mental age of 3-6 years
• Profound learning disabilities indicates an IQ = 20, or mental age of less than 3 years

Average IQ is 100. The arbitrary cut-off to indicate learning disabilities is 70.

Assessing a person’s range of skills provides a more useful way of working out the extra support they require, and identifying goals for further learning and training.

A person with an IQ of 20 has a mental age of 3 years. If 35 years old, they will have had 35 years of lifetime experience to learn from, may also have benefited from some additional specific training, and will have the motivations and biological drives of adulthood.

Many people with mild learning disabilities will achieve independence in adult life and may not need much additional support.

Not all adults with learning disabilities will have undergone IQ and / or adaptive behaviour assessments – where this is the case, you need to make a judgment.

Last Updated: 06 February 2015