Absence of nonfatal suicidal behavior preceding suicide death reveals differences in clinical risks

Nonfatal suicidal behavior is the most robust predictor of suicide death. However, only ∼10 % of those who survive an attempt go on to die by suicide. Moreover, ∼50 % of suicide deaths occur in the absence of prior known attempts, suggesting risks other than nonfatal suicide attempt need to be identified to help prevent suicide mortality. We studied data from 4,000 population-ascertained suicide deaths and 26,191 population controls to improve understanding of suicide deaths without prior nonfatal attempts. This study included 2,253 suicide deaths and 3,375 controls with evidence of nonfatal suicidal ideation or behaviors (SUI_SI/SB and CTL_SI/SB) from diagnostic codes and natural language processing of electronic health records notes. Characteristics of these groups were compared to 1,669 suicides with no prior nonfatal SI/SB (SUI_None) and 22,816 controls with no lifetime suicidality (CTL_None). The SUI_None and CTL_None groups had fewer overall diagnoses and were older than SUI_SI/SB and CTL_SI/SB. Mental health diagnoses were far less common in both the SUI_None and CTL_None groups; mental health problems were far less associated with suicide death than with presence of SI/SB. Physical health diagnoses were conversely more often associated with risk of suicide death than with presence of SI/SB. Pending replication, results indicate highly significant clinical differences among suicide deaths with versus without prior nonfatal SI/SB, and suggest that, for a substantial number of individuals at risk for suicide mortality, history of SI/SB does not serve as an effective clinical marker of risk.