Table 4.

Participant timeline (SPIRIT [Standard Protocol Items: Recommendations for Interventional Trials]) showing the schedule of enrollment, interventions, and assessments.

				Study period
				Enrollment		Baseline and allocation		Postallocation
Time point				−12 to −1 week		−2 to −1 week		0-9 weeks (intervention)		9-week follow-up		21-week follow-up
Enrollment
	Eligibility screening (online and phone)		✓
	Informed consent		✓
	Allocation				✓
Interventions
	iDBT-Paina						✓
	Treatment as usual						✓
Assessments
	Primary outcome measure
		Difficulties in Emotion Regulation Scale-18			✓				✓		✓
	Secondary outcome measures
		Numeric Rating Scale			✓				✓		✓
		PROMISb Pain Interference Instrument			✓				✓		✓
		State-Trait Anxiety Inventory			✓				✓		✓
		Beck Depression Inventory			✓				✓		✓
		NIHc Toolbox Perceived Stress			✓				✓		✓
		PTSDd Checklist–Civilian Version			✓				✓		✓
		The Awareness of Social Inference Test			✓				✓		✓
		Medical Outcomes Study Sleep Scale			✓				✓		✓
		Temperament & Character Inventory			✓				✓		✓
		Satisfaction with Life Scale			✓				✓		✓
		COMPAS-We Scale of Wellbeing			✓				✓		✓
		Health Utilization Questionnaire			✓				✓		✓
		Medication & Health Interventions			✓				✓		✓
	Acceptability measures
		DBTf Ways of Coping Checklist			✓				✓		✓
		Usefulness, Satisfaction & Ease of Use							✓		✓
		Patient Global Impression of Change							✓		✓
		Semistructured interview							✓
		Treatment adherence					✓		✓		✓

^aiDBT-Pain: internet-delivered DBT skills training for chronic pain.

^bPROMIS: Patient-Reported Outcomes Measurement Information System.

^cNIH: National Institutes of Health.

^dPTSD: posttraumatic stress disorder.

^eCOMPAS-W: Composure, Own-worth, Mastery, Positivity, Achievement, Satisfaction with Life–Well-being.

^fDBT: dialectical behavioral therapy.