Trauma and Addiction—How to Treat Co-occurring PTSD and Substance Use Disorders

Posttraumatic stress disorder (PTSD) is a disabling psychiatric disorder that develops after an exposure to a severe traumatic event. According to Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 diagnostic criteria, a traumatic event is defined as exposure to actual or threatened death, serious injury, or sexual violence. Exposure to a traumatic event is very common; up to 90% of population has experienced a qualifying traumatic event but only 7.8% develop PTSD over a lifetime. In at-risk populations (such as women, younger persons, military personnel, police officers), its prevalence is much higher. For example, PTSD affects up to 38% of Vietnam War veterans and up to 65% of rape victims over a lifetime. The DSM-5 diagnosis of PTSD consists of four symptom clusters: (1) Intrusion symptoms; (2) Avoidance of stimuli associated with the traumatic event; (3) Negative alterations in cognitions and mood and; (4) Marked alterations in arousal and reactivity. Exposure to multiple traumatic events is associated with more severe PTSD symptomatology, higher functional impairment, and higher comorbidity with mood and anxiety disorders. In addition, many individuals suffer from posttraumatic symptoms that do not meet full criteria for PTSD, such as intrusive and distressing recollections or thoughts, hypervigilance, distressing dreams of the trauma, and psychological reactions to trauma cues.

Individuals with PTSD have elevated rates of comorbid disorders, notably substance use disorders. One large study of general population found alcohol dependence to be the most common co-occurring disorder in men with PTSD, followed by depressive disorder, anxiety disorders, conduct disorder, and drug use disorder. In this study, 51.9% of men and 27.9% of women with PTSD met criteria for substance use disorder (SUD) and the most common substance used (other than nicotine) was alcohol. The National Vietnam Veterans Readjustment Study of Vietnam Veterans found that 74% of combat Vietnam Veterans with lifetime PTSD had comorbid SUD. A more recent study found that among individuals with PTSD, nearly half (46.4%) met criteria for SUD. Looking at it from another perspective, specifically treatment-seeking populations with SUD, there are higher rates of comorbidity with PTSD compared to the general population. For example, in a study of Operation Enduring Freedom/OEF and Operation Iraqi Freedom/OIF veterans seeking care at the Veterans Administration (VA), 63% veterans diagnosed with substance use disorder had comorbid PTSD.

When PTSD and SUD co-occur, this has important clinical implications because individuals who have both disorders have worse outcomes, including higher rates of comorbid mental health disorders and medical problems, more functional impairments across multiple domains, higher rates of hospitalizations, as well as underemployment and homelessness. Patients with PTSD and SUD often suffer from more severe PTSD symptoms than do patients with PTSD alone. Heavy drinkers have been found to report more severe PTSD symptoms than moderate drinkers or nondrinkers.

Given the high rates of comorbidity, accurately screening at risk populations is of great importance. In substance use specialty clinics, screening tools that can be used include the PTSD checklist (PCL). PCL is a 20-item self-report measure that assesses the 20 DSM-5 symptoms of PTSD. It is easy to administer and provides a provisional PTSD diagnosis. In specialty PTSD clinics, screening for substance and alcohol use disorder is similarly important and there are several commonly used and validated screening tools. These include CAGE questionnaire and the Alcohol Use Disorders Identification Test (AUDIT-C). The CAGE questionnaire is a combination of four simple screening questions, with two or more positive answers indicating a positive history of alcoholism; however, it is nonspecific for current use. The AUDIT-C is a 3-item alcohol screen that can help identify patients who are hazardous drinkers or have active alcohol use disorders.

There are several strategies that can be used to treat comorbidity, and they include pharmacotherapy interventions and behavioral treatments. While there are other reviews that have been published reviewing pharmacotherapy approaches, this review will focus on practical information for clinicians as well provide insight into future directions. Since there is a growing literature specifically evaluating medications to treat these disorders, clinicians can make evidence-based decisions on the best treatment strategies to address these issues. A review of the behavioral treatments is beyond the scope of this chapter, but for a recent review see Simpson et al.