Posttraumatic stress disorder (PTSD) is characterized as a psychological reaction to actual or threatened death, serious injury, or sexual violence [1]. Over 90% of service members and veterans deployed post-9/11 have been exposed to at least one type of traumatic event during their deployments [2] and up to 32% of military service members and veterans have been diagnosed with PTSD [3, 4]. Comorbid health conditions, such as headaches, traumatic brain injury (TBI), and depression have been shown to worsen overall PTSD symptom presentation [5]. Another common co-occurring disorder with PTSD is tinnitus, but it is unknown how it affects PTSD symptom presentation.
Tinnitus is defined as a phantom auditory perception, in one or both ears, without an objective noise source [6]. Types of tinnitus percept include ringing, buzzing, or a rushing sound; the intensity frequency and duration of these percepts vary among individuals [7]. Tinnitus-related distress includes the cognitive, emotional, and behavioral symptomatic sequalae related to the experience of chronic tinnitus. The symptom clusters of tinnitus-related distress are heterogeneous and affects cognitive and emotional well-being [8, 9] and can include symptoms of anxiety and depression [10].
Military personnel have a much higher risk of developing tinnitus due to significant exposure to acoustic trauma through proximity to military aircraft [11], weapon use [12], and combat-related hazards such as car bombs, improvised explosive devices (IEDs), incoming mortar attacks, and rocket-propelled grenades [13]. Exposure to acoustic trauma increases the likelihood of developing tinnitus before, during, and after deployment [14]. Although the defining symptoms of tinnitus (an illusory auditory percept) and PTSD (a trauma disorder) are distinct, their prevalence rates indicate a possible connection between the two disorders.
First, a chart review of veterans treated over a four-year period indicated that 34% of veterans with tinnitus also carried a PTSD diagnosis [15]. Upon closer examination, tinnitus-related distress and PTSD may reflect common sources and/or symptoms. The same psychologically traumatic event could contribute to both PTSD and tinnitus (e.g., IEDs, car bomb). Tinnitus can be conceptualized as a conditioned stimulus, reminding the individual of the traumatic event (Criterion B of PTSD) [1]. In a study of Cambodian refugees with PTSD symptoms, an overwhelming 92% of that cohort reported that flashbacks were accompanied by tinnitus [16], suggesting the relationship between tinnitus and re-experiencing symptoms of PTSD. The same study demonstrated that tinnitus-associated negative mood and cognitive symptoms also predicted PTSD severity. Other studies have reported heightened symptoms of avoidance [15], hypervigilance, and hyperarousal [17] among tinnitus patients, representing Criterion C and E of PTSD, respectively.
There is strong evidence to support involvement of a shared neurobiological mechanism between tinnitus and PTSD. The auditory vigilance network (A1/VAN) is highly implicated among PTSD patients [18]. In fact, the auditory network contains the most regions that differentiate veterans with PTSD versus combat-exposed veterans and civilians without PTSD [19]. The A1/VAN is also the most frequently implicated network in patients with tinnitus [20–22]. Another study found dysregulated connectivity within the A1/VAN, and higher connectivity between the A1/VAN and the visual cortex among PTSD patients [18]. These findings suggest that the genesis and maintenance of tinnitus and PTSD may involve similar neurobiological substrates and/or processes.
Other studies point to exacerbation of tinnitus-related distress as a function of psychiatric distress. Between 32% and 45% of individuals with tinnitus also suffer from anxiety disorders [23], indicating a potentially strong psychiatric component of tinnitus-related distress, either as a premorbid factor or with tinnitus onset. The same study showed that 40% of individuals with tinnitus also reported a family history of psychiatric disorders. Functional outcomes for individuals with both tinnitus and PTSD are also significantly worse than for those with tinnitus only, or tinnitus and any other psychological disorder [17]. This finding suggests especially deleterious outcomes when tinnitus co-occurs with PTSD. Investigation of innovative approaches to the simultaneous management of both conditions is warranted.
Current models borrowed from the chronic pain literature suggest that functional outcomes can be improved when psychological factors are targeted. The biopsychosocial model [24, 25] incorporates biomedical factors, behaviors, emotions, cognitions, cultural values, social support, and socioeconomic status as factors to more fully understand the origins of pain. Framed within the biopsychosocial model, the fear-avoidance model describes a cycle initiated by pain, followed by a constellation of cognitive, emotional, and behavioral responses that may reinforce pain and disability [26, 27]. A key component of the fear-avoidance model is its identification and restructuring of maladaptive cognitions related to the pain or to the implications of painful sensations. Catastrophic cognition, for example, can lead to a cascade of consequences, including overestimation of future pain, avoidance of activities, and physical deconditioning, resulting in reduced levels of function [28]. The fear-avoidance model emphasizes the connection between psychiatric distress and chronic pain, which is further supported by neurobiological [29] and psychological studies [30–32] studies. It is likely that PTSD, tinnitus, and chronic pain all manifest central nervous system changes that persist long after original external or peripheral trauma. It is reasonable to consider that evidence-based therapies for one of these conditions (e.g., PTSD) may also serve to reduce distress associated with another (e.g., tinnitus).
Cognitive processing therapy [33] is one such evidence-based psychotherapy for PTSD. Studies have demonstrated that CPT is efficacious among childhood sexual and physical abuse survivors [34, 35], female sexual assault survivors [36] and military service personnel and veterans [37–41]. Meta-analyses have also shown that CPT has the largest mean effect size compared to any other treatment for PTSD [42–44]. CPT usually consists of 12 sessions, each lasting 50–60 minutes. Patients learn how to recognize dysfunctional thoughts (“stuck points”) that are related to the traumatic experience and larger themes of safety, trust, power and control, esteem, and intimacy. Moving forward in therapy, patients challenge these stuck points and learn how to develop more realistic thoughts, acceptance of the traumatic event, and experiencing natural emotions associated with the trauma.
The alleviation of PTSD may serve to decrease tinnitus-related distress in two ways. First, since tinnitus-related distress and PTSD share common symptoms [15–17], reduction of avoidance, improved emotional and cognitive flexibility, and reduced reactivity may extend to reduce tinnitus-related dysfunction. Additionally, according to the biopsychosocial and fear-avoidance models, PTSD patients who change their dysfunctional beliefs and learn to experience more positive emotions through evidence-based psychotherapy may also benefit by reduced tinnitus-related distress.
The current study investigated the relationship between PTSD-related psychiatric distress and tinnitus-related distress. Based on the reasoning of the biopsychosocial and fear-avoidance models, we expected that negative emotional, cognitive, and behavioral states associated with PTSD serve to exacerbate tinnitus-related distress. Therefore, it was hypothesized that from baseline to one month post-treatment follow-up, individuals with PTSD and bothersome tinnitus who received CPT would experience decreased PTSD symptoms as well as decreased tinnitus-related distress.