Importance of Comorbid Disorders to Suicide Risk in PTSD

Abstract

The aim of this chapter is to explore the role of comorbid disorders in predicting suicidal ideations, plans, attempts, and completed suicide in individuals with post-traumatic stress disorders (PTSD). Recent relevant publications and reviews were selected which assessed a range of comorbid disorders for their ability to (i) partly or fully explain the relationship between PTSD and suicidal behaviors or (ii) combine with PTSD to compound the risk of suicidal behaviors. The findings are not unanimous and based largely on cross-sectional samples, but the majority found that PTSD predicted suicidal ideation, plans and attempts, which also compared well with relevant reviews. In addition, PTSD may specifically predict suicide attempts without a plan, and while relevant meta-analyses recommend further investigation on the link between PTSD and completed suicide, recent studies suggest PTSD is a risk factor for completed suicide. Most studies assessing the combined effect of PTSD and a comorbid condition on suicidal behaviors have reported the combined excess risk to be less than the sum of the separate excess risks associated with PTSD and the comorbid condition. However, comorbidity with alcohol and substance use disorders, phobias, and personality disorders may leave individuals with PTSD at elevated risk for suicidal behaviors compared with other comorbid disorders. The available evidence suggests that PTSD has an independent and clinically meaningful effect on the risk of suicidal ideation, attempts, and completion, with a stronger impact on attempts. In general, the effect of PTSD combined with a comorbid disorder is less than the sum of the two separate effects. However, some specific comorbid diagnoses are potentially more predictive of suicidal behavior among individuals with PTSD than others.