Cognitive symptoms are common during and following episodes of depression. Little is known about the persistence of self-reported and performance-based cognition with depression and functional outcomes.

This is a secondary analysis of a prospective naturalistic observational clinical cohort study of individuals with recurrent major depressive disorder (MDD; N = 623). Participants completed app-based self-reported and performance-based cognitive function assessments alongside validated measures of depression, functional disability, and self-esteem every 3 months. Participants were followed-up for a maximum of 2-years. Multilevel hierarchically nested modelling was employed to explore between- and within-participant variation over time to identify whether persistent cognitive difficulties are related to levels of depression and functional impairment during follow-up.

508 individuals (81.5%) provided data (mean age: 46.6, s.d.: 15.6; 76.2% female). Increasing persistence of self-reported cognitive difficulty was associated with higher levels of depression and functional impairment throughout the follow-up. In comparison to low persistence of objective cognitive difficulty (<25% of timepoints), those with high persistence (>75% of timepoints) reported significantly higher levels of depression (B = 5.17, s.e. = 2.21, p = 0.019) and functional impairment (B = 4.82, s.e. = 1.79, p = 0.002) over time. Examination of the individual cognitive modules shows that persistently impaired executive function is associated with worse functioning, and poor processing speed is particularly important for worsened depressive symptoms.

We replicated previous findings of greater persistence of cognitive difficulty with increasing severity of depression and further demonstrate that these cognitive difficulties are associated with pervasive functional disability. Difficulties with cognition may be an indicator and target for further treatment input.

Major Depressive Disorder (MDD) is prevalent, often chronic, and requires ongoing monitoring of symptoms to track response to treatment and identify early indicators of relapse. Remote Measurement Technologies (RMT) provide an exciting opportunity to transform the measurement and management of MDD, via data collected from inbuilt smartphone sensors and wearable devices alongside app-based questionnaires and tasks.

To describe the amount of data collected during a multimodal longitudinal RMT study, in an MDD population.

RADAR-MDD is a multi-centre, prospective observational cohort study. People with a history of MDD were provided with a wrist-worn wearable, and several apps designed to: a) collect data from smartphone sensors; and b) deliver questionnaires, speech tasks and cognitive assessments and followed-up for a maximum of 2 years.

A total of 623 individuals with a history of MDD were enrolled in the study with 80% completion rates for primary outcome assessments across all timepoints. 79.8% of people participated for the maximum amount of time available and 20.2% withdrew prematurely. Data availability across all RMT data types varied depending on the source of data and the participant-burden for each data type. We found no evidence of an association between the severity of depression symptoms at baseline and the availability of data. 110 participants had > 50% data available across all data types, and thus able to contribute to multiparametric analyses.

RADAR-MDD is the largest multimodal RMT study in the field of mental health. Here, we have shown that collecting RMT data from a clinical population is feasible.

No significant relationships.

Major depressive disorder (MDD) is the second leading cause of disability in China.

To analyze functioning during the course of treating MDD in China, Taiwan and Hong Kong.

To study the influence of pain and clinical remission on functioning.

This was a post-hoc analysis of a 6-month, prospective, observational study (n = 909) with 422 patients enrolled from China (n = 205; 48.6%), Taiwan (n = 199; 47.2%) and Hong Kong (n = 18; 4.2%). Functioning was measured with the Sheehan Disability Scale (SDS), pain with the Somatic Symptom Inventory, and severity of depression with the Quick Inventory of Depressive Symptomatology-Self Report 16 (QIDS). Patients were classified as having no pain, persistent pain (pain at any visit) or remitted pain (pain only at baseline). A mixed model with repeated measures was fitted to analyze the relationship between pain and functioning.

At baseline, 40% of the patients had painful physical symptoms. Patients with pain had a higher QIDS and lower SDS (P < 0.05) at baseline. At 6 months, patients with persistent pain had lower functioning (P < 0.05). The regression model confirmed that clinical remission was associated with higher functioning at endpoint and that patients with persistent pain had lower functioning at endpoint when compared with the no pain group.

Patients presenting with pain symptoms had lower functioning at baseline. At 6 months, pain persistence was associated with significantly lower functioning as measured by the SDS. Clinical remission was associated with better functional outcomes. The course of pain was related to the likelihood of achieving remission.

The authors have not supplied their declaration of competing interest.