Post-Traumatic Stress Symptoms' Association with Depression and Violent Ideation in a Chronically Homeless Sample

Background: Post-Traumatic Stress Disorder (PTSD) and Major Depressive Disorder (MDD) frequently co-occur. The PTSD hyperarousal symptom cluster has been found to covary with violent ideation among persons with co-occurring substance use disorders. Persons with co-occurring homelessness and serious mental illness (SMI) are often at increased risk for victimization, post-traumatic stress, and depressive symptoms. However, DSM-5 PTSD symptom clusters may have various relationships with these associated factors. This study examines associations of PTSD symptom clusters with depression and violent ideation in homeless adults experiencing SMI. Focusing on the relationships among PTSD’s underlying symptom clusters allows for a clearer understanding of the dynamics of PTSD with commonly occurring behavioral health conditions in an often high-needs population.

Methods: The study used data from a community mental health center gathered during a SAMHSA-funded program to expand services to chronically homeless adults in a Midwestern US city (N=210). Participants were linked to mental health and substance use services through street outreach and partnerships with local healthcare facilities. Self-report measures assessed for DSM-5 trauma symptoms clusters (re-experiencing, avoidance, negative alterations in cognition and mood [NACM], alterations in arousal and reactivity [AAR]) using the PCL-5, cognitive and somatic depressive symptoms using the PHQ-9, and ideation about seriously harming others and difficulty controlling violent behaviors in the past 30 days. Four multiple linear regression models analyzed the relationships of PTSD symptom clusters with cognitive and somatic depressive symptoms and violent ideation.

Results: The sample was primarily African-American (61%) and male (65%,) with a mean age of 43.13 years (SD=11.79). Ninety-four percent endorsed experience of at least one lifetime trauma, and 21% reported physical victimization in the past month. Mean scores for trauma (M=40.99, SD=19.00) and depressive symptoms (M=13.75, SD=6.63) were above suggested clinical cut off guidelines. Thirty-six percent reported either thinking about seriously harming another or finding it hard to control violent behaviors in the past month. In regression analyses, somatic symptoms of depression were associated significantly with each PTSD symptom cluster, but most strongly with AAR (β=.809, p<.001). Cognitive symptoms of depression were associated with both re-experiencing (β=.349, p<.01) and NACM (β=.813, p<.001) symptoms. Violent ideation was significantly associated only with AAR (β=1.962, p<.001).

Conclusions and Implications: The overlap between (a) NACM and cognitive depressive symptoms and (b) AAR and somatic depressive symptoms may be attributed, in part, to symptoms shared among MDD and PTSD. This study supports similar research of the shared distress between PTSD and MDD, which has been studied in veteran and primary care samples. The association between cognitive depression and re-experiencing symptoms may be attributed to the role of intrusive thoughts in each disorder and the visceral re-living of traumatic memories. Increased violent ideation was associated with increased AAR, suggesting the need for interventions to support safe coping and safe environments for chronically homeless adults experiencing high rates of victimization. For homeless service providers, assessment for trauma and traumatic stress should be conducted alongside more common screenings for depression, given the high co-occurrence of each in homeless populations.