Endesa Costanera S.A

As discussed above, a primary symptom experienced by PTSD patients is alterations in memory. These debilitating memory symptoms are most consistently observed in both deliberate and involuntary memory related to the traumatic episode (van der Kolk and Fisler, 1995). Most prominent are frequent and distressing involuntary memories, which are often accompanied by difficulties with deliberate memory processes (van der Kolk and Fisler, 1995), as will be discussed in the following.

1.2.2.1 Involuntary memory alterations in PTSD

Spontaneous or intrusive memories that involuntarily enter consciousness are thought to be a normal phenomenon in daily life (Berntsen and Rubin, 2008). However, spontaneous memories that concern a highly negative event, such as trauma, are often reported as being more salient than other memories and may become highly repetitive and distressing to the individual (Holmes et al., 2005). Indeed, after experiencing a traumatic event, people often report involuntary memories that are typically focused on emotional and perceptual details of the event (Ehlers et al., 2004; Arntz et al., 2005). More recently, it has been suggested that involuntary memories might play a central role in several other psychiatric disorders in addition to PTSD, including obsessive-compulsive disorder (OCD), anxiety and depression (Brewin et al., 2010; Holmes et al., 2010). Cognitive views emphasize the role of these spontaneous memories as maintaining factors in mental disorders (Ehlers and Clark, 2000).

Intrusive memories in PTSD are typically described as being qualitatively different from other memories. Importantly, memory intrusions in PTSD also appear different to the involuntary memories experienced by people who have been exposed to trauma without subsequently developing PTSD (Ehlers, 2010). Intrusive memories in PTSD are often characterised by a strong sense of re-living the trauma in the present. Furthermore, in extreme instances, PTSD patients report dissociating completely from the present (Ehlers et al., 2004). Studies have indicated that aspects of the trauma that are most often remembered is what happened immediately before the trauma or at the beginning of what patients found was the worst part of

31 the trauma, also referred to as ‘hotspots’ of trauma memory (Holmes et al., 2005; Ehlers et al., 2002). Emotional aspects of the intrusive memories also set PTSD patients apart from others who have experienced trauma; for instance, PTSD patients often report that their intrusive memories are more distressing than trauma- survivors who do not suffer from PTSD (Ehlers, 2010).

Memory intrusions in PTSD may be triggered both by external and internal (such as thoughts, feelings) cues (Brewin, 2001a; Berntsen and Hall, 2004) and it has been suggested that perceptual priming plays a central role in the disorder (Ehlers et al., 2006; Brewin and Holmes, 2003, Ehlers and Clark, 2000). Perceptual priming refers to an enhanced tendency for trauma-related stimuli to trigger memories of the trauma (Schacter, 1992; Sünderman et al., 2013; Ehlers et al., 2006). This enhanced priming can lead to patients feeling that memory intrusions occur with no apparent reason. In addition, people suffering from PTSD might respond emotionally to a situation that is similar to the trauma without consciously recognising the link to the traumatic experience (Ehlers, 2010; Ehlers et al., 2004). Also, memory intrusions in PTSD are often characterised by having a weak temporal organisation and patients may have difficulties recalling details from the trauma. Finally, memory intrusions may show lack of context, resulting in memories not being updated with other (and perhaps contradicting) information (Ehlers et al., 2004).

1.2.2.2 Alterations in deliberate memory in PTSD

Concurrent with these intrusion symptoms, several studies have found that deliberate memory, that is, memories that can be consciously recollected, retrieved and verbalised, is impaired in PTSD compared to both healthy controls and people who experienced trauma without developing PTSD (Johnsen and Asbjørnsen, 2008, van der Kolk and Fisler, 1995). Evidence for this impairment comes from diverse PTSD studies including studies with war veterans (Golier and Yehuda, 2002; Koso and Hansen, 2006), holocaust survivors (Yehuda et al., 2004) and from victims of abuse (Bremner et al., 2004; Jenkins et al., 1998).

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People suffering from PTSD may experience trauma-related amnesia, displaying difficulties with voluntary recollection of details from the trauma (van der Kolk and Fisler, 1995, Briere and Conte, 1993). Several studies have also found that deliberate recall of the traumatic experience in PTSD patients tends to be fragmented, poorly organised and characterised by a weak temporal structure (e.g. Halligan et al., 2003; Jones et al., 2003, van der Kolk and Fisler, 1995; Brewin, 2016). For instance, Halligan et al. (2003) investigated impairments in voluntary memory in PTSD based on the cognitive theory of PTSD where it is suggested that PTSD symptoms arise as a result of enhanced data-driven (perceptual and sensory) processing during trauma at the cost of conceptual processing (Ehlers and Clark, 2000). Here, the researchers found that data-driven and self-referent peri-traumatic processing during trauma was associated with subsequent development of PTSD. As it will be described later in more detail, the role of processing both during and in the aftermath of trauma has been the subject of extensive research.

In some instances, PTSD patients will suffer from what is known as psychogenic amnesia, the inability to remember central aspects of the trauma (Golier and Yehuda, 2002). It is not known if psychogenic amnesia is caused by insufficient memory encoding or if it alternatively reflects post-encoding factors such as suppression or forgetting (Golier and Yehuda, 2002). Furthermore, studies have suggested that people who were exposed to trauma as children may show global impairments in voluntary memory (van der Kolk and Fisler, 1995) although this notion has received little empirical support (Evans et al., 2009, Ehlers, 2010).

Taken together, these unusual memory phenomena, including disruptions to voluntary memory and increased involuntary memory experiences, are widely reported by patients and seem to form a primary part PTSD (Brewin and Holmes, 2003).