Symptom co-fluctuations with suicidal ideation over time: a dynamic time warp analysis

Suicidal ideation (SI) is a major global concern, yet its dynamic interplay with other symptoms remains poorly understood.

To identify symptoms that co-fluctuate with or temporally precede SI to better understand symptom dynamics.

Longitudinal data from three Dutch psychiatric cohorts with lifetime internalising disorders (16 waves from April 2020 until February 2022) were collected during the COVID-19 pandemic. We analysed depressive, happiness, anxiety, loneliness, worry symptoms and COVID-19-specific items only in those participants with SI fluctuations. Dynamic time warping (DTW) quantified within-person similarity between symptom trajectories and SI and results were aggregated at the group level.

307 participants (mean age 44.8 years; 61.6% female) showed increasing SI over time (p<0.001). In the undirected analysis, SI aligned with four depressive symptoms (ie, sad mood, low self-esteem, low interest and reduced happiness), two anxiety-related symptoms (ie, fear of losing control, faintness) and overwhelming worrying, whereas the interpersonal symptoms feeling abandoned and feeling lonely did not survive false discovery rate (FDR) corrections. In directed analysis, while sad mood, hypersomnia, numbness and worrying about projects initially demonstrated temporal precedence, no directed lead-lag relationships survived FDR correction.

SI is embedded in a broad symptom network beyond depression. These results underscore the value of time-sensitive, idiographic monitoring using tools like DTW to capture the person-specific temporal pathways through which SI emerges and intensifies.

This study suggests a core group of affective, cognitive and distress-related symptoms that could serve as informative signals for evaluating changes in SI and may represent actionable targets for intervention.