Shift-work Disorder
Conditions
Keywords
Sleep reactivity
Brief summary
The purpose of this project is to test sleep reactivity as an independent cause of Shift Work Disorder (SWD). The primary hypothesis is that those with high sleep reactivity will show persistent SWD symptoms after experimental reduction of circadian misalignment, which will then be mitigated with CBT.
Detailed description
The first aim of this study is to establish sleep reactivity as a predictor of insomnia in SWD independent from circadian misalignment. The second aim of this study is to establish sleep reactivity as a predictor of sleepiness in SWD independent from circadian misalignment. The third aim of this study is to probe sleep reactivity as a cause of insomnia in SWD. The fourth aim of this study is to probe sleep reactivity as a cause of sleepiness in SWD. Participants with Shift Work Disorder (SWD, N=150) with high and low sleep reactivity will be enrolled. This study will use a two-step mechanistic randomized controlled trial design stratified by high and low sleep reactivity to examine the independent effect of sleep reactivity in SWD after experimental reduction of circadian misalignment. The first step will experimentally reduce circadian misalignment compared to a control. Those who achieve reduced circadian misalignment (melatonin onset at or later than 4am, i.e., compromised phase position) and remain symptomatic will continue to the second step where sleep reactivity will be probed with CBT compared to a sleep education control.
Interventions
BEHAVIORALActive phototherapy
Timed bright light exposure delivered in a controlled laboratory setting (10,000 photopic lux) designed to delay the DLMO to 4 am or later.
BEHAVIORALControl phototherapy
Timed less intense light exposure delivered in a controlled laboratory setting (100 photopic lux) that still has a perceptible alerting effect but is not designed to shift circadian phase.
BEHAVIORALCognitive Behavioral Therapy (CBT)
Cognitive strategies will identify stressors (e.g., dysfunctional beliefs about sleep) and intervene on worry and rumination with cognitive reappraisal and active coping. Sessions will be conducted by a trained behavioral sleep medicine provider via telemedicine to increase accessibility.
BEHAVIORALSleep education control
Sleep duration recommendations will be equivalent to the CBT group (8 hours of sleep opportunity) to ensure that outcomes are not confounded by time in bed. Materials in the sleep education control condition will be separated into weekly electronic materials monitored for engagement and completion.
Sponsors
National Heart, Lung, and Blood Institute (NHLBI)
Henry Ford Health System
Study design
Allocation
RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
OTHER
Masking
DOUBLE (Subject, Investigator)
Intervention model description
Two-step mechanistic randomized controlled trial design stratified by high and low sleep reactivity. Step 1: active versus control light therapy; Step 2: Cognitive Behavioral Therapy (CBT) versus sleep education control.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Participants must be working a fixed nightshift schedule, operationalized as: a) working at least three night shifts a week, b) shifts must begin between 18:00 and 02:00, and last between 8 to 12 hours, and c) must also plan to maintain the nightshift schedule for the duration of the study * Participants must have Shift Work Disorder, which will be diagnosed based on ICSD-3 criteria * Participants must show circadian misalignment, operationalized as a baseline melatonin onset between 18:00 and 01:00. * Participants must be at least 18 years old
Exclusion criteria
* Insomnia disorder or excessive sleepiness predating the onset of shift work * Termination of nightshift schedule * Presence of other sleep disorders (e.g. obstructive sleep apnea, narcolepsy) determined by standard clinical polysomnography * Diagnosis of bipolar disorder * History of neurological disorders determined by self-report and medical history * Pregnancy * Alcohol use disorder * Illicit drug use via self-report and urine drug screen if reasonable suspicion to test
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Dim light melatonin onset | Within two days of treatment for a duration of 24 hours | Melatonin values will be measured in saliva samples, collected in dim light conditions in a laboratory, to determine circadian phase. |
| Sleep reactivity | Within two weeks of treatment | Sleep reactivity will be measured using the validated Ford Insomnia Response to Stress Test (FIRST). Based on psychometric testing of the FIRST, a cutoff score of 16 will distinguish high and low sleep reactivity. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Insomnia | Within one week of post-treatment | Insomnia will be measured with the Insomnia Severity Scale (0 to 28; higher scores correspond to worse severity) |
| Sleepiness | Within one week of post-treamtnet | Sleepiness will be measured with the Epworth Sleepiness Scale (0 to 24; a score of 10 or greater indicates excessive sleepiness). |
Countries
United States
Contacts
Primary ContactPhilip Cheng, PhD
Backup ContactMarleigh Treger, BS
Outcome results
None listed