Design: This study will use a Multiple Baseline Single Case Experimental Design (SCED). This design has been chosen as it can test the effectiveness of an intervention on a small number of participants. This is of benefit as it allows the piloting of a novel intervention, which brief Cognitive Behavioural Therapy for Insomnia (bCBTi) for those with dissociative seizures will be. It will involve each participant being randomly assigned to a baseline phase of three possible lengths: 5 days, 7 days and 9 days. This will be done using https://www.randomizer.org/ which will generate a random order of the three categories. During the baseline phase, sleep difficulties and levels of dissociation will be measured on a daily basis. The participant will then begin the intervention phase, where they will receive two sessions of bCBTi. Sleep difficulties and levels of dissociation will continue to be measured on a daily basis during the intervention phase. Participants can therefore serve as their own controls. The multiple baseline element controls for time as a confounding variable which increases the study's internal validity, and allows the relationship between variables to be viewed as causal rather than correlational. Guidelines for constructing good quality SCEDs have been used to inform the study protocol.

Recruitment: The study will take place at the William Quarrier Scottish Epilepsy Centre (WQSEC), recruiting current inpatients who meet the criteria for inclusion in the study. Potential participants will be identified and approached initially by the clinical nurse specialist (CNS) on the ward who has access to patient information and is alerted of any new inpatients. The CNS will provide the potential participant with an information sheet, and ask if they would consent to the principal investigator speaking to them to go through it, answer any questions and obtain informed consent. If the participant agrees to participating, the baseline measures will also be completed at this stage. Overall, the recruitment stage should take around 1 hour of participant's time over a couple of days.

Baseline phase: The participant will then enter a randomly assigned baseline phase of 5, 7 or 9 days in length, which will involve them completing two short measures on a daily basis and wearing an actiwatch during the night. It will take around 10-15 minutes to complete the measures each day. Nursing and/or Health Care Assistants on the ward may assist with prompting participants to complete the measures throughout the duration of the study if they have capacity in addition to their primary clinical duties.

Intervention phase: Once they have completed their baseline phase, they will begin the intervention phase, which will involve attending two sessions of bCBTi with a clinical psychologist on the ward. Each session will last between an hour to an hour and a half. The sessions will be three days apart, one on a Monday and one on a Friday. The participants will continue to complete daily measures during this time, and will continue to wear the actiwatches.

Post-intervention phase and study completion: Following the two sessions of bCBTi, the participants will continue to complete the daily measures and wear the actiwatch for 7 days. Following this, the principal investigator will meet with the participants to complete the post intervention measures, which are the same as the pre-intervention measures. At this meeting, the principal investigator will also debrief the participants on the study. This meeting will take around an hour.