Robert H. Pietrzak, PhD, MPH

US Department of Veterans Affairs National Center for PTSD, VA Connecticut Healthcare System, West Haven, Connecticut; Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut; Department of Social and Behavioral Sciences, Yale School of Public Health, New Haven, Connecticut

JCP
A Growing Epidemic of Loneliness among US Military Veterans
Brief Report

August 3, 2026

The prevalence of frequent loneliness increased significantly compared with 2019–2020 estimates. Frequently lonely veterans had significantly greater odds of 6 of 8 psychiatric disorders, such as depression and PTSD.
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PCC
Cardiovascular Disease and PTSD in Older Veterans
Original Research

July 14, 2026

Older veterans with comorbid CVD and PTSD have a markedly elevated burden of health and functional difficulties, underscoring the importance of integrated, trauma-informed care to improve outcomes in this...
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PCC
Primary Users of the VA Health Care System
Original Research

June 18, 2026

Sociodemographic and clinical profiles of veterans who primarily rely on the VA for health care reveal a vulnerable group who tend to have more complex psychiatric and medical needs.
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JCP
Predictive Modeling of Suicidal Ideation in US Veterans: PHQ-2 Versus Complex Machine Learning Approaches
Original Research

June 17, 2026

Machine learning models provided a statistically significant, yet clinically modest, performance improvement over the PHQ-2 sum score.
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JCP
National Trends in PTSD among US Military Veterans
Original Research

May 25, 2026

Compared with 2019–2020, past-month PTSD prevalence was higher among men, White and racial/ethnic minority veterans, and veterans aged 18–59 years
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JCP
Dissociative Subtype of PTSD in US Military Veterans
Brief Report

February 4, 2026

Of 169 veterans who screened positive for past-month PTSD, 87 screened positive for the dissociative subtype of PTSD.
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JCP
Geographic Differences in Cannabis Use and Cannabis Use Disorder in the US Veteran Population
Original Research

January 19, 2026

Significant regional differences were observed in cannabis use and cannabis use disorder (CUD). Veterans in the Pacific region had the highest rates of cannabis use and CUD.
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JCP
Identifying Factors Linked to PTSD Among Younger US Military Veterans
Original Research

September 17, 2025

Younger veterans were 3 times more likely to screen positive for PTSD compared to older veterans, with psychosocial difficulties contributing most to this association.
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JCP
Psychosocial Correlates of Optimism among US Military Veterans
Brief Report

April 21, 2025

Positive psychosocial characteristics (PPCs) such as curiosity, perceived resilience, and purpose in life were strongly linked to optimism scores, suggesting a role for interventions that target other PPCs in...
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JCP
Ketamine Infusions and Written Exposure Therapy for Chronic PTSD
Original Research

April 2, 2025

Preliminary findings suggest that the combined treatment may yield large and durable symptom reductions for patients with severe chronic PTSD
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PCC
Suicide-Specific Cognitions in US Military Veterans
Original Research

January 14, 2025

This study examined data from a large, nationally representative sample of US veterans to determine the prevalence and correlates of high chronic suicide risk.
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JCP
Sex Differences in PTSD among US Military Veterans
Brief Report

December 16, 2024

Sex differences in PTSD were attributable to differential exposure to traumatic events such as childhood sexual assault and military sexual trauma and to social factors such as greater loneliness.
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