Sleep Treatment Outcome Predictors: A Pilot Study (STOP-pilot)

Changes in insomnia symptoms as assessed by scores on the Sleep Condition Indicator (SCI). This pilot aims to establish the distributional properties of individual differences in change score on this measure. The scale has a theoretical range of 0-32. A higher score indicates fewer insomnia symptoms. Therefore a positive change score (>0) indicates fewer insomnia symptoms at the end of the intervention compared to baseline. A negative score (<0) indicates more symptoms at the end of the itnervention compared to baseline.

Changes in sleep quality as assessed by scores on the Pittsburgh Sleep Quality Index (PSQI). This pilot aims to establish the distributional properties of individual differences in change score on this measure. The scale has a theoretical range of 0-21. The change score reflects the change in symptoms at each assessment compared with baseline. Higher scores on the indicate worse sleep quality. Therefore for the change score, a positive value indicates worse sleep quality at the assessment time period compared to baseline. A negative value indicates better sleep quality at the assessment time period compared to baseline.

Acceptability of the CBT-I in an unselected sample will be assessed, and measured using an adapted version of the Treatment Acceptability Questionnaire (TAQ) suitable for use with an online therapist. The TAQ has a theoretical range of 6-42, with a higher score indicating higher levels of treatment acceptability.

Acceptability of the CBT-I in an unselected sample will be assessed, and measured using an adapted version of the Treatment Acceptability Questionnaire (TAQ) suitable for use with an online therapist. The TAQ has a theoretical range of 6-42, with a higher score indicating higher levels of treatment acceptability.

Change in treatment acceptability across the CBT-I treatment will be assessed, through changes in the score on the Treatment Acceptability Scale. Acceptability of the CBT-I in an unselected sample will be assessed, and measured using an adapted version of the Treatment Acceptability Questionnaire (TAQ) suitable for use with an online therapist. The TAQ has a theoretical range of 6-42, with a higher score indicating higher levels of treatment acceptability. Therefore a positive change score means an improvement in treatment acceptability, whereas a negative change score indicates a reduction in treatment acceptability.

Drop-out rate will be assessed as the percentage of those who consented to take part in the study who did not complete the study.

Anxiety as a predictor of response to treatment outcome, as measured using the Trait State Anxiety Index. The theoretical range is 20-80, and a higher score indicates more anxiety symptoms at baseline

Anxiety as a predictor of response to treatment outcome, as measured using the Mood and Feelings Questionnaire. The theoretical range is 0-26, and a higher score indicates more anxiety symptoms at baseline

Attentional problems as a predictor of response to treatment outcome, as measured using the ADHD symptoms questionnaire. The theoretical range is 1-54, and a higher score indicates more attentional problems at baseline

Psychotic experiences as a predictor of response to treatment outcome, as measured using the Specific Psychotic Experiences Questionnaire. Subsacles measuring paranoia (theoretical range 0-25), hallucinations (theoretical range 0-25), and cognitive disorganization (0-5) were used. On all subscales, a higher score indicates more psychotic experiences at baseline

Positive mental health as a predictor of response to treatment outcome, as measured using the Positive Mental Health Scale. The theoretical range is 1-36, and a higher score indicates higher levels of positive mental health at baseline

Stress as a predictor of response to treatment outcome, as measured using the Perceived Stress Scale. The theoretical range is 5-50, and a higher score indicates more perceived stress at baseline

Threatening life events as a predictor of response to treatment outcome, as measured using the List of Threatening Events. The theoretical range is 0-24, and a higher score indicates more exposure to threatening events in the 12 months preceeding baseline

Anxiety symptoms, measured using the State Trait Anxiety Index. The theoretical range is 20-80, and a higher score indicates more anxiety symptoms at baseline.

Depression symptoms, as measured using the Trait State Anxiety Index. The theoretical range is 0-26, and a higher score indicates more depression symptoms.

Attentional problems, as measured using the ADHD symptoms questionnaire. The theoretical range is 1-54, and a higher score indicates more attentional problems.

Psychotic experiences, as measured using the Specific Psychotic Experiences Questionnaire. Three subscales measuring paranoia (theoretical ragne 0-25), hallucinations (0-25), and cognitive disorganization (0-5) were used. On all subscales, a higher score equals more frequent experiences

Positive mental health, as measured using the Positive Mental Health Scale. The theoretical range is 1-36, and a higher score indicates higher levels of positive mental health.

Perceived stress, as measured using the Perceived Stress Scale. The theoretical range is 5-50, and a higher score indicates higher levels of perceived stress.

Sleep paralysis is a relatively common but understudied phenomenon that has the potential to cause large amounts of fear and/or distress in individuals who experience it. As an exploratory analysis, it shall be investigated whether individuals assigned to the CBT intervention who also experience sleep paralysis show any reductions in the frequency of episodes, and associate levels of fear/distress throughout the programme.

As this isn't a main aim of the study, this aim is dependent upon a sufficient number of participants who experience sleep paralysis being present in the sample. It is unlikely that there will be sufficient power to thoroughly assess this, but it is hoped this will provide helpful information to future studies.

Exploding head syndrome is an unusual and understudied phenomenon associated with sleep. Measures included in this study shall be used in an exploratory fashion to perform a cross-sectional analysis looking at associations between exploding head syndrome and factors such as sleep problems, depression, anxiety, and well-being.

Exploding head syndrome was measured using a 1-5 scale, where 1 = never experienced and 5 = several times a week. Sleep paralysis was measured using a 1-7 scale ranging from 1 = never observed to 7 = several times a week.