Major Depressive Disorder: Early Prediction of Non-response to Antidepressant Therapy Via a Mobile Digital Scale

Major Depressive Disorder (MDD) is a debilitating disease characterized by a depressed mood, diminished interests, impaired cognitive function and vegetative symptoms, such as disturbed sleep or appetite. MDD occurs about twice as often in women than it does in men and affects about 6% of the adult population worldwide each year.

Standard symptoms scales like the Hamilton Depression Rating Scale or the Montgomery-asberg Depression Rating Scale, the Self-Report 16-item Quick Inventory of Depressive Symptomatology were initially developed for the evaluation of a therapeutic intervention or a pharmacological treatment and are routinely used by clinicians in the assessment of Treatment Resistant Depression (TRD) occurrence. In parallel, patient-reported outcomes have gained increasing importance and are widely recommended by health authorities in the assessment of depression. The same institutions insist on the collection of real-world data to provide clinicians with ecological measurements. It has been demonstrated that an early response to an AntiDepressant (AD) treatment can be seen as early as week 2 and is not related to a placebo-effect. While there is no consensus on the exact cut-off values, several factors emerge as early predictors of a later treatment response, such as:

• Improvement in emotional processing of happy facial expressions after 1 week of treatment,
• Circa 20% improvement in Hamilton Depression Rating Scale-17 item (HDRS-17) at week 2. The hypothesis is therefore that repeated, systematic and real-time, contextualized and multimodal collection of depressive symptoms from patients at home will establish a threshold score that can predict a subsequent response to their treatment.

REDRESS was inspired by several standard depression scales used and recommended by the French Health Authority, augmented with digital active and passive activity monitoring, speech analysis and emotional processing assessment. Another important assumption is that honesty and willingness to disclose personal or embarrassing things will be best achievable via a digital solution.

To test this assumption, the overall scores and each subscores on the REDRESS numerical scale will be compared in people with MDD showing adequate response to those showing insufficient response.

The response to treatment at week 6 will be studied (end of Phase 1). Non-responders and responders to the first treatment round will be enrolled in a 6-week extension phase (Phase 2). Non-responders will receive another treatment course (Other AD, combination, etc.). Responders will just be followed up and will keep the same treatment. The REDRESS scores will be analysed in this population and will allow us to test the investigator's assumption in people with treatment resistant depression. This study will also allow to assess patients' quality of life at the end of each phase of treatment and to compare results with REDRESS scores.