What is in a name? Definitions of insomnia in people with intellectual disabilities

The reported prevalence of insomnia symptoms in people with intellectual disabilities varies greatly, possibly due to the lack of a common definition. This article provides an overview of the different definitions used and formulates key points for a general definition.

A literature search was performed. An overview of the definitions used was given and compared to the third edition of the international classification of sleep disorders.

The search yielded 16 studies. No uniform definition was used. Terminology and cut-off points of insomnia symptoms differed. Insomnia symptoms were mostly described as night-time problems. A minority of studies incorporated daytime consequences.

An insomnia disorder entails more than merely night-time complaints and should include daytime consequences. A general definition is warranted. This definition should focus on night-time and daytime insomnia symptoms, incorporate subjective features, and discuss the use of objective measurements and influence of environmental circumstances.