Japanese FIRST tool assesses vulnerability to insomnia

By Joanna Lyford, Senior medwireNews Reporter

The Japanese version of the Ford Insomnia Response to Stress Test (FIRST-J) has been validated and confirmed as a reliable tool for assessing vulnerability to insomnia in healthy individuals.

“[T]he measure is expected to become an important trait marker for insomnia in Japanese individuals,” remark Yuichi Inoue (Tokyo Medical University, Japan) and fellow researchers writing in Sleep Medicine.

The FIRST is a self-administered questionnaire that assesses stress-induced sleep reactivity through nine items relating to situational sleep-disturbing stimuli. Items are scored on a Likert scale to give a total score from 9 to 36, with higher scores indicating lower sleep efficiency, longer sleep-onset latency, and increased proportion of stage 1 sleep.

In this study, Inoue et al developed a Japanese version of the FIRST and used it to assess 161 healthy volunteers (53 women, mean age 51.5 years) and 177 patients (101 women, mean age 46.8 years) diagnosed with insomnia.

The FIRST-J showed good internal consistency and factorial validity in both healthy participants and insomnia patients, Inoue et al report. Furthermore, as anticipated, mean scores on the FIRST-J were significantly higher in insomnia patients than in controls, at 24.0 versus 18.6.

Interestingly, in healthy individuals, FIRST-J scores significantly correlated with scores on three other validated tools, namely, the Pittsburgh Sleep Quality Index, the Athens Insomnia Scale, and the State-Trait Anxiety Inventory (STAI).

In people with insomnia, by contrast, FIRST-J scores significantly correlated with the STAI but not with the two insomnia-specific tools.

Taken together, this suggests that sleep reactivity is related to trait anxiety, which is known to be a determinant of vulnerability to insomnia, the authors propose.

Meanwhile, the lack of correlation between FIRST-J and other insomnia measures in patients with insomnia might indicate that sleep reactivity is related to vulnerability to insomnia but does not play a major role in processes aggravating insomnia.

The team concludes: “The FIRST-J is an important tool for assessing vulnerability to insomnia.”

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