Youth Suicide and Self-Harm Intervention: Clinical and Biological Outcomes Study

The DSI-SS is a 4-item self-report questionnaire designed to assess the frequency and intensity of suicidal ideation and impulses. Scores range from 0 to 12, with higher scores indicating greater severity of suicidality; a score of 3 or higher is considered the clinical cut-off for high suicide risk.

The FASM assesses the methods and frequency of non-suicidal self-injury (NSSI), as well as the functions maintaining the behavior. It distinguishes between Internal Functions (e.g., emotion regulation) and Social Functions (e.g., influencing others). The instrument yields data on the total frequency of self-mutilative behaviors and separate scores for these functional domains.

The SHSI is a 10-item self-report measure used to screen for non-suicidal self-injury (NSSI) behaviors over the past year. It assesses 10 specific methods of self-harm (e.g., cutting, hitting, overdosing) performed without the intent to die. Each item is scored as 0 (No) or 1 (Yes). Total scores range from 0 to 10; a score of 1 or higher (indicating any experience of self-harm) is the cut-off for recommending a visit to a psychiatrist.

Circadian rhythm stability refers to the consistency of 24-hour rest-activity patterns across days, as assessed using wrist-worn actigraphy.

Inter-daily Stability (IS) quantifies the degree of similarity between daily activity profiles across consecutive days, with values ranging from 0 to 1. Higher IS values indicate greater stability and synchronization of the circadian rest-activity rhythm.

These researcher-defined items assess the frequency of Non-Suicidal Self-Injury (NSSI) and suicide attempts. NSSI frequency is measured across four timeframes (lifetime, past year, past month, past week) using a 7-point ordinal scale ranging from 'Once' to '50 times or more'. Suicide attempts are assessed by total lifetime frequency (4-point scale) and the recency of the most recent attempt. Higher scores on frequency items indicate a greater number of incidents.

The Social Rhythm Stabilization Score assesses the regularity of daily routines (e.g., sleep, activities) through the completion of a daily social rhythm log. Variability is derived using 'Max-Min' for durations and 'Circular Time Distance' for clock times. Lower values indicate greater stability. Scores are categorized as: Very Regular (≤ 30), Regular (31-60), Mildly Variable (61-90), Variable (91-120), Irregular (121-180), and Very Irregular (> 180).

The BIS-II is a 23-item questionnaire designed to assess the personality construct of impulsiveness. Total scores range from 23 to 92, where higher scores indicate higher levels of impulsiveness.

The DERS-SF is an 18-item self-report measure used to assess difficulties in emotion regulation. Scores range from 18 to 90, where higher scores indicate greater difficulty in emotion regulation.

The DTS is a 15-item self-report measure of emotional distress tolerance. Scores range from 15 to 75, with higher scores indicating higher levels of distress tolerance (i.e., better capacity to withstand distress).

The GAD-7 is a 7-item instrument used to assess the severity of generalized anxiety. Scores range from 0 to 21, with higher scores indicating more severe anxiety symptoms. Severity categories are defined as Mild (5-9), Moderate (10-14), and Severe (15-21). A total score of 10 or greater is the clinical cut-off for identifying probable generalized anxiety disorder.

The PHQ-9 is a 9-item module used to screen for and measure the severity of depression. Scores range from 0 to 27, where higher scores indicate greater severity of depressive symptoms.

The PSS is a 10-item instrument used to measure the perception of stress. Scores range from 0 to 40, with higher scores indicating higher levels of perceived stress. Stress levels are categorized as Low (0-13), Moderate (14-26), and High (27-40).

The RRS-SF is a 10-item measure that assesses rumination in response to depressed mood. Scores range from 10 to 40, where higher scores indicate higher levels of rumination.

The ULS-6 is a 6-item scale designed to measure subjective feelings of loneliness and social isolation. Scores range from 0 to 18, where higher scores indicate higher levels of loneliness.

The PIES is a 10-item instrument that measures the extent to which an individual perceives their emotions as being invalidated by others. Total scores range from 10 to 50, where higher scores indicate higher levels of perceived emotional invalidation.

The RSES is a 10-item scale that measures global self-worth. Scores range from 10 to 40, with higher scores indicating higher self-esteem.

The ISI is a 7-item instrument measuring the nature, severity, and impact of insomnia. Scores range from 0 to 28, with higher scores indicating more severe insomnia symptoms.

The PDSS is an 8-item self-report measure of daytime sleepiness in school-aged children. Scores range from 0 to 32, with higher scores indicating greater daytime sleepiness.

The Sleep Health Index (SHI) is a 16-item instrument that assesses sleep health across three sub-domains: Sleep Quality, Sleep Duration, and Sleep Disorders. Raw scores are converted into a standardized index ranging from 0 to 100. A higher score indicates better sleep health.