Substance Use Disorders and Clinical Management of Traumatic Brain Injury and Posttraumatic Stress Disorder

Substance use disorders, traumatic brain injury (TBI), and posttraumatic stress disorder (PTSD) are common in military and civilian populations, and often occur together. A substantial proportion of military personnel misuse alcohol. A study of the UK armed forces¹ reported that 67% of men and 49% of women had scores of 8 or higher, defined as hazardous drinking, on the Alcohol Use Disorders Identification Test, compared with 38% of men and 16% of women in the general population. In a population-based cohort of US soldiers returning from service in Iraq,² 11.8% reported alcohol misuse on a 2-item alcohol screening test. Recent military service is also associated with TBI, PTSD, and depression. In a 2008 survey,³ 19.5% of US armed services personnel returning from service in Afghanistan and Iraq reported experiencing a possible TBI, 18.5% met criteria for PTSD or depression, and 7.3% both reported a possible TBI and met criteria for PTSD or depression. By comparison, the lifetime prevalence of PTSD estimated for the general US population is 7.8%, and of those 51.9% of men and 27.9% of women have a lifetime prevalence of both PTSD and alcohol abuse or dependence.⁴

Substance use disorders, TBI, and PTSD may occur together for several reasons. Alcohol use, for example, may be a cause or a consequence of TBI. Studies have shown that depending on the setting studied, 18% to 66% of patients with TBI have a history of alcohol abuse,⁵ and one-third to one-half of persons with TBI are intoxicated at the time of their injuries.⁶ This is not surprising, considering that alcohol use is a recognized risk factor for motor vehicle injuries, falls, and violence, all of which are important causes of TBI. Hazardous drinking may also persist after TBI. A recent Australian study⁵ reported that hazardous drinking initially decreased after the TBI event and then increased by 2 years postinjury to 25.4% of the cohort.

Traumatic brain injury has been reported to be associated with PTSD,⁷ and PTSD may be associated with substance use disorders by an indirect association with TBI. However, PTSD is often associated with substance use disorders, presumably in the absence of TBI. According to a model of the development of PTSD, the key features can all lead to substance use problems.⁸ In this model, the predisposing neurobiological alteration is hyperarousal—a rapid, extreme, and prolonged reaction to stressors. Hyperarousal leads to a maladaptive preoccupation with signs of threat or internal distress known as hypervigilance. This in turn leads to avoidance of people, places, thoughts, and feelings associated with threat or distress, which in turn leads to emotional numbing and social detachment. An inability to process and integrate trauma memories leads to intrusive reexperiencing of unpleasant associations. Each of these features, according to this model, can lead to substance use problems, by means of self-medication with alcohol or other drugs in an attempt to relieve anxiety, increase alertness, avoid traumatic memories, increase emotional numbing and social detachment, or regain the ability to feel pleasure or experience connections with other people.

Neurological deficits associated with TBI may explain the increased susceptibility of brain-injured individuals to PTSD and substance use disorders. Although the magnitude, type, and point of impact of the external force will affect the location and extent of damage, the frontal areas of the brain are the most vulnerable under typical injury circumstances such as crashes and assaults that create acceleration/deceleration forces. As a result, the “fingerprint” of TBI is bruising to the frontal lobes and the anterior tips of the temporal lobes, as well as shearing and tearing of axon sheaths and neuron bundles connecting to the frontal lobes.⁹ The frontal lobes of the human brain control functions essential for complex social behavior, particularly the ability to inhibit emotion, plan goal-directed behavior, and manage thinking skills. Posttraumatic stress disorder may be associated with TBI because functions of the medial prefrontal cortex are integral in learning to inhibit the fear reactions associated with PTSD.¹⁰

Characteristic cognitive impairments associated with TBI include slowed processing speed, difficulty with multitasking, and reduced cognitive endurance.⁹ Patients with more severe brain injuries may have difficulty with more complex components of executive functioning, such as goal selection, planning, and error correction. Formerly routine cognitive tasks may require greater effort or even seem overwhelming. Frustration with cognitive impairments combined with impaired regulation of mood can lead to depression, which has been observed in 25% to 50% of patients with TBI.⁹

The goals of therapy for substance use disorders and PTSD may be viewed as complementary. Enhancing the ability of patients to replace impulsive behaviors with reflective reality-based decisions is just as critical for managing the cravings for substances and patterns of behavior that sustain addiction as it is for coping with intrusive traumatic memories characteristic of PTSD.⁸ However, according to a meta-analysis of 26 studies of psychotherapy for PTSD,¹¹ 16 of the studies (62%) excluded patients with substance use disorders. Consequently, the generalizability of PTSD treatments to patients with coexisting substance abuse is uncertain. Other evidence suggests that therapy for substance use disorders may be adversely affected by undetected and untreated PTSD,⁸ and conversely that integrating therapy for substance use disorders and PTSD may improve both PTSD symptoms and substance use. A controlled trial of patients with co-occurring alcohol dependence and PTSD found that patients who had significant improvement in hyperarousal symptoms drank alcohol less often and consumed fewer drinks on drinking days.¹²

Symptoms of TBI present additional challenges to the successful treatment of coexisting PTSD. A standard treatment for PTSD is cognitive behavioral therapy, a technique for helping patients confront trauma memories or cues, develop skills for anxiety management, and challenge distorted cognitions.¹¹ Typically, cognitive behavioral therapy is highly structured, which is a therapeutic advantage for patients with TBI.¹³ However, accommodations may have to be made for such patients who have slowed processing speed, reduced cognitive endurance, and have difficulties with planning and error correction.¹³ A recent systematic review¹³ identified 3 randomized controlled trials of psychological treatments for anxiety in patients with TBI and judged 2 of them to be of sufficient methodological quality to permit interpretation. The first trial found a benefit of cognitive behavioral therapy, which included imaginal exposure to traumatic memories, cognitive restructuring, and graded exposure to the avoided situation. The second trial found a benefit of an intervention that combined cognitive behavioral therapy with neurorehabilitation, defined as remediation of attention, information processing, and memory difficulties and assistance with organization and problem-solving skills. The third trial had compromised methodological quality, reflective of the problems common to studies in this area.

The clinical management of patients with TBI and coexisting substance use disorders may also require innovative approaches to achieve treatment objectives. A trial of interventions to promote retention in substance abuse treatment for patients with co-occurring TBI found that financial incentives to study participants improved appointment attendance during the first month of treatment.¹⁴ In addition, better attendance was associated with greater therapeutic alliance as perceived by both the patient and the therapist. Impulsiveness and an orientation toward immediate reinforcement with less regard for long-term consequences may be characteristic of substance use disorders as well as TBI. Therefore individuals with TBI and substance use disorders may more easily commit to treatment if they can be given a concrete incentive to attend initial treatment sessions.

The co-occurrence of behavioral health problems may place additional demands on treatments designed for one of these conditions in isolation. What is not clear is whether simple accommodations (eg, compensatory strategies in the case of co-occurring TBI) or other minor adaptations to treatment are all that is needed, or whether a fundamentally different treatment approach is required. For example, the treatment demands for individuals dually diagnosed with substance use disorders and severe mental illness spawned Integrated Dual Disorders Treatment (IDDT).¹⁵ This treatment approach introduced ideas such as holistic case conceptualization and individualized staging of treatment components to better address the complexity of the clinical manifestation of co-occurring disorders. The complexity of substance use disorders co-occurring with PTSD, TBI, or both may necessitate that new treatment concepts be developed to successfully address these combined disorders. A systematic program of research and, if indicated, treatment development is a high priority, particularly for formerly deployed military personnel who are experiencing TBI, PTSD, and substance use disorders.