Introduction: Past incidence of severely elevated suicidal ideation (lifetime worst point ideation) is a risk factor for later suicide attempt and suicide death even in the absence of an actual past suicide attempt. The specific contribution of severely elevated ideation to such risk is poorly understood.
Methods: Samples of depressed patients ages 16-80 were recruited from three sites (Columbus, OH; Pittsburgh, PA; New York, NY) in the AFSP-funded Lifespan Neurocognition study. Patient groups were: (1) currently depressed patients with at least one past suicide attempt (ATT, n=99), (2) depressed patients without past suicide attempt but with worst point suicidal ideation that fell within the range of past attempters’ (retrospective Beck Scale for Suicidal Ideation > 16; HiWP-NATT, n=32), and (3) patients without past suicide attempt and lower levels of worst point ideation (LoWP-NATT, n=59). Groups were compared on clinical and neurocognitive measures to determine how nonattempters with high worst point ideation resembled or differed from suicide attempters and low worst point nonattempters.
Results: HiWP-NATT differed significantly from LoWP-NATT and were comparable to ATT in their being younger (p=.001), having earlier age of onset (p<.001), greater objective (p=.004) and subjective depression severity (p=.014), current suicidal ideation (p<.001), hopelessness (p<.001) and feelings of entrapment (p=.042). They exhibited comparably poor social problem solving skills (p=.038), slower reasoning speed (p=.028), and slower overall response times (p=.002). Stroop performance, a measure often associated with past attempt, was poorest in HiWP-NATT (P=.035). The only differences observed between HiWP-NATT and ATT were the HiWP-NATT group’s reduced degree of physical aggressiveness (p=.009), poorer mindful attention awareness (p=.048), and mildly lower degree of past suicidal ideation at its worst point (p<.001).
Conclusions: Nonattempters with a past history of severely elevated suicidal ideation at its worst point strongly resembled suicide attempters on numerous clinical and neurocognitive factors associated with elevated risk for suicidal behavior. Very high worst point ideation may be as significant a risk factor for subsequent suicidal behavior as a prior suicide attempt itself, when accompanied by other risk factors. HiWP-NATT is a critical group in which to characterize risk and resilience in future studies of suicidal behavior.