The DIF, PSQI, VAS, and BDI were also administered to individuals in the control group during the first interview, but no education was provided to them. The participants were given an appointment to meet at the hospital one month later. At the final polyclinic appointment one month later, the VAS, PSQI, and BDI were administered for the second time and took an average of 15-20 minutes to complete. In line with ethical principles, they were provided with individual education on sleep hygiene and sleep hygiene education booklets at the final polyclinic appointment. The same researcher collected the data and provided the education to avoid bias.

During the first interview, the DIF, PSQI, VAS, and BDI were administered to individuals in the experimental group. Each education session lasted an average of 30 minutes and was conducted face-to-face. Sleep hygiene education booklets were provided to individuals at the end of the education session. Studies suggest that at least one month should pass for behavioral change to occur after the education session. Therefore, the participants were given an appointment to meet at the hospital one month later. At the final interview one month after the education, the VAS, PSQI, and BDI were administered for the second and final time and took an average of 15-20 minutes to complete.

The sleep hygiene education booklet was prepared by the researchers by in line with the literature. The booklet contains information on the definition and benefits of sleep, sleep problems during insomnia, arrangements for regular sleep, and the principles of sleep hygiene. The principles of sleep hygiene include individual habits that facilitate sleep, proper arrangement of the physical environment, exercises before going to bed, and dietary habits. This educational content was applied to those in the experimental group. The education took an average of 30 minutes.

This form was prepared by the researcher based on the literature and consists of 10 questions about the FM patients' sociodemographic and disease characteristics (age, gender, educational status, etc.).

The PSQI evaluates the quality of sleep in the last month. It consists of 19 items and 7 components. Each item is evaluated on a 0-3 point scale, and the sum of scores from seven components gives the total PSQI score. The total score ranges from 0 to 21. A high total score indicates poor sleep quality. A total PSQI score of ≤5 indicates "good sleep," while a score of >5 indicates "poor sleep." The Cronbach's alpha value of the scale is 0.80. In this study, the Cronbach's alpha was found to be 0.83.

The VAS is a valid and reliable scale to measure the intensity of chronic pain. It is rated from "0 = no pain" to "10 = worst possible pain". The intervals for pain intensity are <3 for mild pain, 3-6 for moderate pain, and >6 for severe pain. The Cronbach's alpha value of the scale is 0.97. In this study, the Cronbach's alpha was found to be 0.92.

The scale consists of a total of 21 items. The highest possible total score is 63. A high total score indicates a higher level of depression. The severity of depression is categorized as follows: 0-9 = minimal, 10-16 = mild, 17-29 = moderate, and 30-63 = severe depression. The internal consistency coefficient of the scale is 0.86. In this study, the Cronbach's alpha was found to be 0.83.