Comment by OutOfHere

That is true. From section 2.6 of the full-text:

> The sleep disturbances were assessed using the Athens Insomnia Scale [ 19], a self-administered psychometric questionnaire designed to evaluate sleep disorders, particularly insomnia [ 20 ]. It consists of eight items rated on a Likert scale ranging from 0 “no problem at all” to 3 “very severe” [ 20]. The total score ranges from 0 (absence of any sleep-related problems) to 24 (the most severe degree of insomnia). Severity is classified as normal for scores of 3 or less, subclinical insomnia for scores of greater than 3 but less than 6, and clinical insomnia for scores of 6 or more [19,21,22].