Although many children with CdLS have no significant behavioural problems, there are some conditions, which makes self-injurious behaviour more likely to occur: pain, discomfort, frustration or dismay. The typical young person with CdLS may be described as hypersensitive and dysrhythmic. He/she may be hypersensitive in that he/she may have strong reactions to ordinary stimuli and these reactions may continue long after the stimulus is gone. He/she is sometimes dysrhythmic, that is having irregular patterns of behaviour in the areas of eating, sleeping and emotional response.

The lack of sensitivity to pain and/or heightened sensitivity to touch suggests some individuals may have neurological impairment. They may also be prone to behavioural problems such as hyperactivity, short attention span, and oppositional or repetitive behaviour.