Lifestyle Intervention for Symptoms of Depression wIth App Support in General Practice

To assess the PLI's cost-effectiveness from a societal perspective, the Treatment Inventory of Costs in Patients with psychiatric disorders (TIC-P) will be used. The main outcome in the cost-effectiveness analysis is Quality-Adjusted Life-Years (QALYs) based on the EQ-5D-5L, measuring general quality of life.

Also, additional treatments are measured within the TIC-P, for secondary analysis on additional care.

Change in quality of life will be assessed using the EQ-5D-5L. This tool consists of 5 dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression, with each rated on a 5-level scale. The EQ-5D-5L also includes a visual analog scale (VAS) to assess overall health. Higher scores indicate better quality of life, while lower scores reflect greater limitations or discomfort. This measure helps track changes in health status and overall quality of life over time.

To evaluate the effectiveness of the PLI on depression symptomatology, general symptoms of depression will be assessed using the Patient Health Questionnaire-9 (PHQ-9). The PHQ-9 is a 9-item self-reported questionnaire assessing the severity of depression symptomatology. The PHQ-9 is brief, easy to complete, and takes only a few minutes to fill out. The total score ranges from 0 to 27. Scores are interpreted as follows: 0-4 indicates minimal or no depression, 5-9 mild depression, 10-14 moderate depression, 15-19 moderately severe depression, and 20-27 severe depression. Higher scores suggest more severe symptoms, and professional treatment is recommended as the score increases.

To measure the severity of anxiety symptoms, the GAD-7 (Generalized Anxiety Disorder-7) will be used

Quality of life is measured using the Recovering Quality of Life (ReQol) questionnaire, a patient-reported outcome measure specifically developed for individuals with various mental health conditions. The ReQol provides a total score ranging from 0 to 80, with higher scores reflecting a better quality of life and overall recovery outcome.

Use of antidepressants, when started/ended, type, dosage, and at follow-up: inquire about changes.

Use of anxiolytics by self-reported questions about the use of sedatives/sleep medication, when started/ended, frequency of use, type, dosage, and at follow-up: inquire about changes.

Self-constructed questions about the daily lifestyle habits of all participants. The lifestyle components addressed include smoking, alcohol consumption, drug use, sleep duration, adherence to the Dutch Physical Activity Guidelines according to the Dutch National Institute for Public Health and the Environment (RIVM), and nutrition based on the dietary recommendations of the Netherlands Nutrition Centre.

Weight and height will be combined to report BMI (Body Mass Index) in kg/m^2.

In the intervention group, self-constructed questions about lifestyle are used to measure a patient's satisfaction with specific lifestyle components on a scale from 0 to 10, where 10 indicates the highest level of satisfaction. The lifestyle components include mental wellbeing, minimizing harmful substances, social relationships, healthy eating, sleep, and physical activity. It is possible that someone smokes but is currently satisfied with this and does not wish to make any changes. The intervention is not intended to impose certain behaviors but rather to address the lifestyle components that the individual is willing and motivated to improve, with the ultimate goal of reducing depressive symptoms. These questions collectively provide an overview that the healthcare provider and patient can use together to set achievable goals. In the control group, this questionnaire will only be completed at month 6 of the study.

The Consumer Quality Index (CQI) is a 16-item questionnaire that evaluates patient experiences and satisfaction across various dimensions, such as communication, access to care, and treatment outcomes. The CQI helps healthcare providers track patient experiences and identify opportunities for enhancing care. It has a 5 point scale. The last item is a scoring item for overall treatment satisfaction. Higher scores indicate better satisfaction, while lower scores highlight areas for improvement.

The Patient-Doctor-Relationship Questionnaire (PDRQ-9) is a patient-reported outcome measure used to assess the quality of the therapeutic relationship between patients and their healthcare providers, such as general practitioners (GPs) or mental health nurses (GP-MHNs). The questionnaire evaluates key aspects of the patient-provider interaction, helping to capture the perceived level of trust, support, and communication. The score ranges from 9 to 45, higher score indicating a more positive relationship according to the patient.

Social support will be measured using the SSL12 (Social Support List-12) questionnaire. This validated tool assesses perceived social support across various domains, such as emotional, practical, and informational support. Higher scores indicate greater perceived social support, while lower scores suggest limited support. The SSL12 helps evaluate the level of social assistance individuals feel they receive and can track changes in social support over time.

Secondary analysis of PHQ-9 outcomes. To evaluate the effectiveness of the PLI on depression symptomatology, general symptoms of depression will be assessed using the Patient Health Questionnaire-9 (PHQ-9) every 6 weeks. The PHQ-9 is a 9-item self-reported questionnaire assessing the severity of depression symptomatology. The PHQ-9 is brief, easy to complete, and takes only a few minutes to fill out. The total score ranges from 0 to 27. Scores are interpreted as follows: 0-4 indicates minimal or no depression, 5-9 mild depression, 10-14 moderate depression, 15-19 moderately severe depression, and 20-27 severe depression. Higher scores suggest more severe symptoms, and professional treatment is recommended as the score increases.

To assess the PLI's cost-effectiveness from a societal perspective, the Treatment Inventory of Costs in Patients with psychiatric disorders (TIC-P) will be used. The main outcome in the cost-effectiveness analysis is Quality-Adjusted Life-Years (QALYs) based on the EQ-5D-5L, measuring general quality of life. At 3 and 12 months, an incremental analysis is done in addition to the cost-effectiveness at 6 months

Baseline demographics include gender, age, education level, employment status and ethnicity.

The List of Threatening Experiences (LTE, developed bij Brugha) measures the occurrence of 12 major categories of stressful life events (did you experience this: No, yes in the last 6 months, yes longer ago) The Dutch translation includes an additional thirteenth question: "Did you experience any other major severe negative events (yes/no)? If yes, briefly describe what happened?" The questionnaire is offered at baseline, and at 6 months a shorter version (did you experience this in the last 6 months?).

Item scores are summed to derive a total score. Higher score indicates more threatening experiences.

History of depression and previous psychological treatment are assessed through self-reported questions. These include the number of previous depressive episodes treated, the number of hospitalizations for depression in a psychiatric hospital or mental health institution, age of onset, duration of the current episode (when it began), family history of depression, and any previous psychological treatment or psychotherapy.

Chronic diseases will be evaluated using questions of the TIC-P questionnaire e.g., health status, lung diseases, heart diseases, blood vessels, diabetes, stroke, joint degeneration, rheumatism, cancer, high blood pressure, and other diseases.

This questionnaire comprises questions about psychiatric diagnoses and treatment (in the last 6 months , ever or never), other than depression.

Meta-data in the Patient Journey App will be tracked and analyzed. Meta-data includes application usage data such as the frequency of app openings, the number of times patients access information, and which features or sections are most frequently used or viewed.

The mHealth App Usability Questionnaire (MAUQ) is a 21-item survey scored on a 7 point likert scale from 1 (disagree) to 7 (agree) with higher scores indicative of higher usability. For this study, the subscales MAUQ-E (8 items on Ease of use and satisfaction) and MAUQ-U (7 items on Usefulness) will be used.