This point is also made by Yehuda, Flory, Pratchett, Buxbaum, Ising and Holsboer (2010), who report that early life stress can also increase the risk of developing PTSD and there may even be a genetic component involved that predisposes some people to developing PTSD. Studies of Vietnam combat veterans have shown that the type of exposure variables that were encountered (i.e., severe personal injury, perceived life threat, longer duration, intensity, complexity and exposure to the suffering of others), can adversely affect the symptomological course of the condition, meaning that the type of trauma that is experienced is also a risk factor in the development of PTSD (Cockram et al., 2010). Studies have also shown, though, that post-trauma factors such as stress management skills and social support systems can help to mitigate the development of PTSD as well as help facilitate recovery from the condition (Cockram et al., 2010).

The body of research on the onset of PTSD indicates that various aspects of the social support construct predict the development of PTSD. Interpersonal stressors (such as friction and negative social reactions) and interpersonal resources (such as availability of emotional, instrumental, and perceived support) each predict PTSD onset (Laffeye et al., 2008). Negative social factors (i.e., interpersonal stressors such as friction and negative social reactions to trauma disclosure) are more predictive of PTSD than positive social factors (i.e., such as availability of emotional support, instrumental support, and support satisfaction) (Laffeye et al., 2008). It has been proposed that negative social factors may emerge following trauma exposure through a path that is separate from the path between trauma and positive social factors. Thus, it is important for research on the relationship between social support and PTSD to examine both negative and positive social factors (Laffeye et al., 2008).

The symptoms of PTSD. One of the more perplexing aspects of PTSD is the different ways it manifests in different people, with some cases involving several years or even decades between the traumatic episode and the emergence of symptoms. Once they occur, though, the symptoms of PTSD can be truly debilitating and even life-threatening. For instance, according to Kearney et al., (2012), "Symptoms of PTSD often persist for decades, and typically result in major disruptions in interpersonal relationships, physical comorbidity, substance abuse, affective disorders, impaired ability to work, and a high rate of attempted suicide" (p. 101). The most common types of symptoms of PTSD include (a) intrusion (i.e., nightmares, flashbacks, intrusive thoughts), (b) constriction (i.e., numbing, disassociation, avoidance), and (c) hyperarousal (i.e., increased vigilance, overly jumpy, insomnia) (Nelson, 2011). In addition, the diagnostic criteria for PTSD include diminished interest or participation in previously enjoyed activities (criterion C4) and a reduced ability to feel emotions, particularly those associated with intimacy, tenderness, and sexuality (DSM-IV, 2000, p. 464). Such diminished interest or participation in previously enjoyed activities is termed anhedonia and Frewen, Dozois and Lanius (2012) report that, "Research also shows that symptoms of emotional numbing may be particularly related to anhedonia" (p. 1).

Comorbid substance use disorder and PTSD has been linked with greater symptom severity, worse treatment outcomes, and increased medical and legal problems than with PTSD alone (Peller, Najavitis, Nelson, LaBrie & Shaffer, 2010). Likewise, the results of a study by Jason, Mileviciute, Aase, Stevens, DiGangi, Contreras and Ferrari (2011) showed that PTSD is associated with increased risk for substance use disorders (SUDs). According to these researchers, "Studies have found rates of PTSD and SUD comorbidity as high as 25-59%. Having PTSD and increased psychiatric distress associated with comorbid disorders is associated with poorer substance use outcomes" (Jason et al., 2011, p. 175). In addition, dually diagnosed patients are less likely to be in remission when compared to an SUD-only group, but that they did have more severe levels of distress. However, other studies suggest that there are no significant differences for treatment outcomes between those with comorbid PTSD and SUD, and SUD-only groups (Jason et al., 2011).

Several theorists believe that using substances for extended periods of time may be a causal factor in mental health symptomatology, or that it exacerbates existing psychiatric symptoms (Jason et al., 2011). The type of substance used or abused may also have different effects of PTSD sufferers. For example, Jason et al. (2011) report that medication theorists assert that individuals use substances as a coping mechanism for negative emotions. Alcohol may have dampening...

There is some evidence for both theoretical points-of-view (Jason et al., 2011).
The symptoms of PTSD typically involve both physiological and psychological responses to traumatic memories that occur following the traumatic episode along a contextual and/or temporal continuum with three groups of symptoms generally occurring together in PTSD as described in Table 1 below.

Table 1

PTSD Symptom Groups

Group

Description

Group B

Intrusion symptoms for this group include re-experience of traumatic memories at night (i.e., nightmares) and during the day (i.e., flashbacks and intrusive recollection of traumatic events with physiological reactivity).

Group C

Symptoms for this group include avoidance of reminders of the trauma (e.g., inability to talk about the experience or return to the site) and numbing of general responsiveness (e.g., emotional numbing, feeling of detachment or estrangement from others, and sense of foreshortened future).

Group D

Hyper-arousal symptoms for this group are insomnia, irritability or outbursts of anger, difficulty concentrating, hypervigilance, and exaggerated startle response.

Source: Adapted from APA, 2000

According to Jovanovic, Norrholm, Blanding, Davis, Duncan, Bradley and Ressler (2010), the first symptom category, referred to as cluster B, covers symptoms of re-experiencing the event, such as intrusive thoughts, nightmares, and flashbacks induced by reminders of the event. Cluster C symptoms include avoidance of stimuli associated with the trauma, while cluster D incorporates symptoms of increased arousal. The latter two symptom clusters include restricted range of affect, emotional detachment, loss of interest, difficulty sleeping, and impaired concentration that are also cardinal symptoms of MDD. Furthermore, suicidality is frequently seen in both disorders. This overlap in clinical presentation of the two disorders has lead some researchers to argue for a distinct depressive subtype of PTSD, rather than the presence of two separate disorders (Jovanovic et al., 2010).

According to Shad et al. (2011), the most common groups are B. And D; however, group C. is regarded as an essential element in the psychopathology of PTSD. The importance of group C. symptoms in the diagnosis of PTSD, however, does not preclude a potentially pivotal role of group B. And D. symptoms in mechanisms involved in the development of PTSD and maintenance of its symptoms. For example, a number of studies have noted that intrusion and hyper-arousal symptoms may predict or even lead to group C. symptoms of avoidance/numbing responses. Since numbing has been proposed to result after effortful avoidance of intrusion symptoms and hyper-arousal fails, prevention or eradication of groups B. And D. symptoms could help to prevent the occurrence of group C. symptoms and ultimately PTSD.

According to Dyer, Dorahy, Hamilton, Corry, Shannon, MacSherry and Elder (2009), these symptom clusters seem effective at explaining the central difficulties of those exposed to singularly occurring, acute traumatic events. However, in isolation they are less well-suited for the spectrum of symptoms and personality disturbance often exhibited by individuals who have experienced prolonged trauma. Consequently, "complex PTSD" or "disorders of extreme stress not otherwise specified" (DESNOS) emerged to account for the organized and complicated array of problems described by those who experience early onset, protracted, and repeated traumatic events usually involving interpersonal victimization. Examples of these complex traumata include torture, childhood abuse, domestic violence, chronic combat exposure, and severe social deprivation (Dyer et al., 2009).

Therefore, the importance of treating intrusion and hyper-arousal symptoms is not only for reduction of these unpleasant symptoms themselves, but also to further reduce the development of avoidance and numbing symptoms that may occur in response to intolerable intrusion and hyper-arousal symptoms (Shad et al., 2011). Post-traumatic symptoms involving sleep are insomnia (a hyper-arousal symptom) and nightmares (an intrusion symptom). Dysregulation of rapid eye movement (REM) sleep is thought to play a pivotal role in the development and persistence of nightmares and other sleep disturbances in PTSD. Sustained increases in brain adrenergic activity have been shown to accompany dysregulation of REM sleep in PTSD. According to Shad et al. (2011), "These findings implicate an overactive, hyper-aroused sympathetic nervous system in the generation of sleep-related PTSD symptoms such as nightmares" (p. 5). Given the centrality of restful sleep to health, sleep-related symptoms have become the focus of an increasing amount of attention from PTSD researchers. For instance, Wright, Britt, Bliese, Adler, Pichionni and Moore (2011) emphasize that, "Sleep disturbances are commonly reported by soldiers returning from combat. The prevalence of sleep problems is not surprising given that sleep disturbance is a diagnostic criterion for posttraumatic stress disorder (PTSD) and is also co-morbid with a range of psychological problems" (p. 1240). These researchers add, though, that there is a growing body of evidence that indicates sleep disturbance plays a key role…