Reducing Maximal Support in OCD: Efficacy of Stepped-Care Online CBT

YBOCS is compiled by Goodman in the United States and contains 10 items to assess the severity of obsessive thoughts and compulsive behavior. The scoring method adopts a five-point scale of 0-4 points, and the total score range is 0-40 points, which has good reliability and validity. Scores below 16 are considered mild or subclinical, 16 to 23 points indicate moderate severity, 24 to 31 points indicate severe severity, and scores above 31 indicate extremely severe.

FOCI, a self-rating scale, is used to assess the severity of obsessive-compulsive symptoms within one month, which contains 20 items. The first 15 items are evaluated the symptoms by yes and no, and the last 5 items are evaluated the severity of symptoms on 0-4 five-point scale. The Chinese version of the FOCI severity scale ≥8 is considered positive (i.e., indicative of obsessive-compulsive disorder).

The Self-Rating Depression Scale (SDS) was developed by William W. K. Zung from the Duke University School of Medicine in 1965 and is one of the most widely used self-assessment scales for depression. It is used to measure the severity of depressive states and their changes during treatment.

According to the Chinese norm results, the cutoff value for the SDS standard score is 53 points, with 53-62 points indicating mild depression, 63-72 points indicating moderate depression, and above 73 points indicating severe depression. The normal upper limit for the SDS total raw score is 41 points, with lower scores indicating a better state. The standard score is the integer part obtained by multiplying the total raw score by 1.25. In China, a SDS standard score ≥50 is considered to have depressive symptoms.

The Self-rating Anxiety Scale (SAS) is very similar to the Self-rating Depression Scale (SDS) from the scale construction to the evaluation method. It is a very simple clinical tool to analyze the subjective anxiety symptoms of patients. It is suitable for adults with anxiety symptoms and has a wide range of application.According to the Chinese norm results, the cut-off value for SAS standard deviation is 50 points, with 50-59 points indicating mild anxiety, 60-69 points indicating moderate anxiety, and above 69 points indicating severe anxiety.

The University of Rhode Island Change Assessment (URICA) is a self-report measurement method developed by McConnaughy, DiClemente, Prochaska, and Velicer . The 24-item version consists of four dimensions: Precontemplation (Cronbach's α = 0.79), Contemplation (Cronbach's α = 0.84), Action (Cronbach's α = 0.84), and Maintenance (Cronbach's α = 0.82). URICA is commonly used to study motivation related to the treatment of behavioral health issues, and few studies have explored the specific relationship between the URICA scales and Cognitive Behavioral Therapy (CBT) for obsessive-compulsive disorder.For the general population, the following cut-off scores may be appropriate:

8 or lower classified as People in Precontemplation 8-11 classified as People in Contemplation 11-14 classified as People in Preparation or Action For intensive service populations, it may be more appropriate to use only score in the range of 12-14 to classify those in preparation and action.

The full name of the self-completed Six-Dimension Health Survey Brief Form (SF-6Dv2) is "Short Form Six-Dimensions version 2". The SF-6Dv2 is an updated version of the widely used SF-36 Health Survey Questionnaire. It is a health utility measurement tool used to assess an individual's health-related quality of life (HRQoL) and convert it into health utility values, which can be used to calculate Quality Adjusted Life Years (QALYs). The SF-6Dv2 includes six dimensions: physical function, role limitation, social function, pain, mental health, and vitality.

The study designs a self-rated questionnaire about cost-effectiveness analyses, including both direct and indirect costs, and the patients themselves fill out the questionnaire based on the bill. The cost-effectiveness analysis method (CEA) is used to measure the spending of three groups. The results of the total cost divided by YBOCS total reduction scores can reflect the cost required to obtain each unit of curative effect.

The cost-utility analysis method is used to measure the spending of improving patients' quality of life. The results of the total cost divided by SF-36 total improvement scores can reflect the cost required to obtain each unit of utility.

Dropout rate is recorded to evaluate treatment acceptability.

Frequency of occurrence is recorded to evaluate treatment acceptability. The investigators use sign-in sheets to measure patients' attendance during the treatment.

Homework completion is recorded to evaluate treatment acceptability. The investigators use sign-in sheets to keep track of patients' homework completion.

Subjective satisfaction with treatment is recorded to evaluate treatment acceptability. The investigators use a self-rated question（"Overall, how satisfied are you with your current treatment?") to measure patients' subjective satisfaction. The rating was done on a 7-item scale ranging from "Extremely dissatisfied" to "Extremely satisfied".

Adverse events (AEs) are the treatment safety indicators

RDM is a classic perceptual decision-making paradigm where participants are required to report the overall direction of motion of 300 randomly moving white dots, with the total task duration being approximately 25 minutes. RDM is often used in conjunction with the drift diffusion model to study human decision-making processes and has been supported by a wealth of research evidence . Following the RDM decision, a confidence assessment phase is added, measuring participants' decision confidence through their subjective reports.

Anti-saccade task is a behavioral paradigm measuring response inhibition ability. Each trial started with a red or green central disc (1°diameter), lasting for 450/600/750/900ms. Participants were instructed to fixate on the central disc. The color (red vs. green) indicated whether the current trial was prosaccade or antisaccade, and the mapping between the color and the trial type was counterbalanced across participants. Then, together with the central disc, a white disc (1° diameter) was presented for 500ms at the left or right border of the grey rectangle. Participants were required to look at the white disc with their eyes given a prosaccade trial, and to look at the opposite location given an anti-saccade trial. Participants were instructed to respond as accurately and quickly as possible. A blank screen of 1500 ms was presented after the target. There were 40 trials in each condition. The total 80 trials were mixed and divided into 4 blocks of equal length.

The investigators use the randomized dot motion perceptual decision-making task as Neuroimaging Paradigm to observe the neurophysiological changes cauesd by step-ICBT in patients with OCD.