The Etiology and Treatment of Co-morbid PTSD and SUDs

Author: Sarah Grace Uhouse, M.S.
Doctoral Student, Clinical Psychology
Rutgers, The State University of New Jersey

Posttraumatic stress disorder (PTSD) and substance use disorders (SUDs) are highly co-morbid. Some estimates indicate that up to one half of SUD-treatment-seeking individuals also meet criteria for PTSD (Berenz & Coffey, 2012), and similarly, approximately half of individuals with PTSD also meet criteria for a SUD (Pietrzak et al., 2011). Clinically, patients with co-occurring PTSD/SUD have a poorer prognosis, such as worse treatment outcomes, higher rates of suicidal and violent behaviors, and reduced social and health-related functioning, compared to individuals who present with only one disorder (McCauley et al., 2012). As such, it is vital to understand the factors that contribute to the high comorbidity rates between these two disorders so that these mechanisms can be targeted in treatment.

PTSD is a disorder classified by exposure to a traumatic event (Criterion A; American Psychiatric Association, 2013) and subsequent failure to recover. Symptoms include trauma-related intrusions (Criterion B), avoidance of trauma-related stimuli (Criterion C), the experience of negative changes in cognition/mood (Criterion D), and arousal/reactivity (Criterion E) as a result of the traumatic experience (American Psychiatric Association, 2013). Individuals must also report experiencing subjective distress or functional impairment in social, occupational, health, or other related domains due to the presence of these symptoms.

SUDs as a category are conceptualized as chronic, relapsing disorders in which individuals experience a compulsive drive to use their substance of choice, an inability to control substance consumption, and a negative affect between use episodes (American Psychiatric Association, 2013). Commonly associated symptoms include increased levels of craving and tolerance as use progresses, and withdrawal if use is reduced or stopped. Like PTSD, to meet criteria for a SUD, individuals must also endorse subjective distress or functional impairment.

The self-medication theory of PTSD/SUD comorbidity has received substantial support from previous studies (Stewart & Conrod, 2003). This theory highlights the fact that PTSD symptoms following a traumatic event, such as hyperarousal and intrusions, are subjectively distressing. In an attempt to attenuate or avoid the experience of PTSD symptoms, individuals may use substances as an effective short-term coping strategy. Over time, however, it becomes necessary to take substances in larger quantities to achieve the same effect or to use substances to avoid withdrawal symptoms. Given the overlap between certain PTSD symptoms and withdrawal symptoms (irritability, sleep disturbance, anhedonia, poor concentration), the experience of these symptom profiles simultaneously serves to negatively reinforce the continued use of substances and exacerbate underlying PTSD symptoms (McCauley et al., 2012).

In certain individuals, however, the SUD precedes, and may even contribute to the occurrence of, the traumatic event. According to the high-risk hypothesis, individuals with SUDs are often involved in lifestyles that promote risky behavior, such as entering dangerous environments in order to obtain the substance of choice or being involved in accidents or violent acts as a result of substance use (Acierno et al., 1999). For these individuals, the use of substances is thought to increase the likelihood that they will experience a traumatic event that will precipitate PTSD symptomology, and some data suggest this may be the truth for certain populations (Haller & Chassin, 2015).

Although the theoretical foundations for understanding the high rate of PTSD and SUD comorbidity are clinically intuitive, there is much debate in the field of psychology as to how to best treat these individuals. Historically, practitioners have followed the sequential model of treatment, where the SUD is treated first while the PTSD diagnosis remains unaddressed. Once the individual has demonstrated a sufficient period of sobriety, trauma work can begin, generally by another clinician (Flanagan et al., 2015). Supporters of this model indicate that the SUD must be treated before the PTSD, as the concern is that exposure to trauma-related stimuli will lead to higher craving and relapse rates in comorbid patients (McCauley et al., 2012). However, there is little evidence to support this model. Instead, research has indicated that integrating PTSD and SUD treatments is actually more effective, likely due to targeting avoidance as a maintaining mechanism of both PTSD and SUDs (Roberts et al., 2015; Simpson et al., 2017). One such treatment is Concurrent Treatment of PTSD and Substance Use Disorders using Prolonged Exposure (COPE; Back et al., 2015). This manual-based treatment integrates prolonged exposure and cognitive-behavioral therapy skills for the treatment of co-occurring PTSD/SUD. Compared to a treatment-as-usual-condition, COPE was found to be more effective at reducing both PTSD and SUD symptoms (Mills et al., 2012).

There is also evidence for the combination of psychotherapy and medication for the treatment of comorbid PTSD and SUD. A recent study by Hien and colleagues (2015) demonstrated that Seeking Safety, a non-exposure based treatment for PTSD and co-occurring alcohol use disorder (AUD), when combined with sertraline (an SSRI), was more effective at reducing PTSD symptoms than a Seeking Safety plus placebo condition. Interestingly, both groups demonstrated statistically and clinically significant reductions in AUD symptoms from baseline, suggesting that Seeking Safety is associated with improvements in AUD severity, even in the absence of medication. 

As clinicians, it can be anxiety-provoking to consider working with patients to confront their PTSD symptoms when the risk of increased substance use is “right around the corner.” Instead, it may be more comfortable to adhere to the staggered model of treatment, where abstinence must be achieved before trauma work. However, the evidence suggests that patients will exhibit higher reductions in both PTSD and SUD symptomology if an integrated treatment approach is taken. In fact, in a 2010 study by Hien and colleagues, results indicated that for every unit of PTSD symptom decrease, there was an associated four-fold decrease in the odds of using substances heavily. Thus, clinicians should familiarize themselves with evidence-based protocols for the treatment of co-occurring PTSD and SUDs, such as COPE and Seeking Safety, and request supervision and consultation on these difficult cases when needed.


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