Table 2 Operationalization of DSM-IV adapted criteria for paediatric insomnia in children with Asperger syndrome or high-functioning autism (n = 32) and in controls (n = 32).

1. The complaint is significant difficulty (defined by frequency, severity, and/or chronicity) initiating or maintaining sleep. The difficulty is viewed as problematic by the child and/or a caregiver;

1. Parent report of a significant sleep problem either

1.1. difficulty initiating sleep ≥ 3 t/week or;

1.2. night-time awakenings ≥ 3 t/week

1.3. difficulty initiating sleep and/or night-time awakenings ≥ 3 t/week

2. The sleep disturbance causes clinically significant impairment in school performance, behaviour, mood, learning, or development for the child as reported by the child and/or a caregiver;

2. Parent-reported consequence of a sleep problem

2.1. distress for the child

2.2. impaired daytime function for the child

2.3. burden for the parents

3. The sleep disturbance does not occur exclusively in the context of an intrinsic dyssomnia such as narcolepsy, restless legs syndrome, or sleep-related breathing disorders; a circadian rhythm disorder; or a parasomnia; and

3. Insomnia does not occur exclusively in the context of another sleep disorder

4. The sleep disturbance is not attributable to either the direct physiologic effect of a drug or the abuse or misuse of a prescribed medication.

4. Insomnia is not attributable to the previous or current medication