Within-person temporal alignment shows symptom co-fluctuations and early precursors of suicidal ideation

BackgroundSuicidal ideation (SI) is a major global concern, yet its dynamic interplay with other symptoms remains poorly understood. ObjectiveTo identify symptoms that co-fluctuate with or temporally precede SI to improve warning signal detection and intervention. MethodsLongitudinal data from three Dutch psychiatric cohorts with lifetime internalizing disorders (16 waves from April 2020 until February 2022) were collected during the COVID-19 pandemic. We analyzed 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 group level. FindingsThe 307 participants (mean age 44.8 years; 61.6% female) showed increasing SI over time (p < .001). SI aligned with four depressive symptoms (i.e., sad mood, low self-esteem, low interest, and reduced happiness), two anxiety-related symptoms (i.e., fear of losing control, faintness), feeling abandoned, and overwhelming worrying. In directed DTW analysis, sad mood, hypersomnia, worrying about projects, and numbness/tingling showed significant temporal precedence before SI. ConclusionSI 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. Clinical implicationsThis study suggests a core group of affective, cognitive, and interpersonal symptoms that could serve as informative signals for evaluating changes in SI and may represent actionable targets for intervention. Summary BoxO_ST_ABSWhat is already known on this topic?C_ST_ABSO_LISuicidal ideation (SI) is a dynamic phenomenon, yet traditional research often relies on static, group-level averages that do not capture individual fluctuations. C_LIO_LIWhile SI is linked to depression, it can emerge independently through complex interactions with other affective and interpersonal states C_LI What this study adds?O_LIThis study identifies a set of affective, cognitive, and interpersonal symptoms, sad mood, overwhelming worry, and feelings of abandonment, that significantly co-fluctuate with SI over weeks and months. Additionally four specific "leading" symptoms, sad mood, hypersomnia, worrying about projects, and somatic numbness, were found that precede increases in SI. C_LI How this study might affect research, practice or policy?O_LIThe identified co-fluctuations and precursors serve as informative "(early) warning signals" that can improve individual risk stratification and clinical monitoring and may represent targets for intervention. C_LIO_LIThe results support a shift toward network-based models in suicidology, emphasizing the need for time-sensitive monitoring to capture the complex and dynamic nature of suicidality. C_LI