Phenotyping suicidal ideation and behavior: Comparing clinical characteristics and future suicide attempts between suicidal subtypes in two clinical samples.

objectivesTo further validate the concept of suicidal subtypes distinguished by indicators of suicidal thinking and behavior with regard to clinical characteristics and past and future suicide attempts.

methodsPsychiatric inpatients were assessed (study 1: ecological momentary assessments in 74 depressed inpatients with suicidal ideation; study 2: clinical assessments in 224 inpatients after a suicide attempt and over a 12-month follow-up period). Subtypes were identified using latent profile analysis (based on indicators of real-time suicide ideation) and latent class analysis (based on features of past suicide ideation and suicide attempt characteristics). Comparisons between subtypes included clinical characteristics (depression, suicidal ideation, trait impulsivity, childhood trauma) as well as past (study 1) and future (study 2) suicide attempts.

resultsSuicidal subtypes emerged that are characterized by suicidal ideation means and stability and features of past suicidal behavior (four in study 1, three in study 2). The subtypes differed in terms of depression/suicidal ideation, but not in terms of trait impulsivity/childhood trauma. Although not significant, the subtypes "high-stable" and "low-moderate stable" reported multiple re-attempts more frequently during follow-up than the "low-stable" subtype in study 2.

conclusionDifferences in clinical variables (and by trend in future suicide attempts) clearly point to the clinical relevance of suicidal subtypes (with variability of suicidal thoughts playing a particularly important role).