Our hypothesis was that a diary explaining what happened to the patient in ICU might help patients fill in gaps in their memories, place any delusional memories into context and aid psychological recovery. The study showed that the provision of an ICU diary, outlining the patients' stay in ICU on a day to day basis, given at one month into the patients' recovery helps to reduce the incidence of new acute-onset PTSD reducing its impact on the patients' long-term quality of life [21
]. ICU patients developing PTSD may be haunted by their memories and may try to suppress them; however, trying not to think about such emotionally charged memories leads to more unbidden thoughts accompanied by greater physiological arousal [22
]. Learning to modulate their feelings and reduce the physiological arousal is the first step to recovery. CBT is recommended for the treatment of PTSD and a similar mechanism may be operating with the diaries because it helps patients to change how they think about their illness as they reread the story and build an autobiographical memory.
There was one slight difference between the study groups at randomisation; there were more females in the control group and at least one study has suggested that high levels of PTSD-related symptoms are more common in women [23
]. However, this is not a consistent finding across studies [2
] and in the control group gender was not related to the development of PTSD in this study.
Family members can suffer from PTSD themselves [24
] and may also be helped by the diaries because it clarifies the story for them too and helps to facilitate communication with the patient about their treatment. In addition writing in the diary when the patient is in ICU may allow them to express some of their feelings. A strong relation has been found between high levels of PTSD-related symptoms in family members and those in patients [24
] so a therapy, such as a diary, that is shared between the patient and the family may be better than one that just concentrates on the patient.
The mechanism behind the development of PTSD is still not clear. Some researchers have focused on noradrenergic activity as a key component of the stress response and tried to manipulate this to reduce the noradrenergic activity and the enhanced startle response, which is part of PTSD [25
]. Other PTSD researchers have suggested that the helplessness experienced at the time of the trauma and the biological effects of being unable to escape lead to the profound changes seen in PTSD [26
]. Ehlers and Clark's [27
] PTSD model hypothesises that it is the quality of an individuals' cognitive processing during a traumatic event that is important in the development of chronic PTSD. Those individuals who report feeling confusion and overwhelmed as they experienced the traumatic situation are more likely to suffer from chronic PTSD. ICU patients' ability to process information is likely to be compromised by a number of factors, such as critical illness, delirium, sleep deprivation, sedative drugs and opiates. They are likely to be unable to process the meaning of the events happening to them and may instead experience delusional events such as hallucinations or nightmares and so be predisposed to high levels of chronic PTSD. A number of studies have examined the influence of giving a β-adrenergic receptor antagonist [28
] or cortisol therapy [30
] to try to reduce the incidence of PTSD; however, these therapies may be problematic in the critical care population and more research is needed to clarify their role.
Concern has been expressed by some that the diaries could be seen as a one-off debriefing session, which have been shown to increase the risk of PTSD [33
]. However, as many patient's memories are fragmentary and much contained in the diary is new to the patient, this seems unlikely and is not supported by the results of this study.
Diaries are not without cost; there has to be a commitment from the staff to write something in the diary every day and take photographs when important changes happen. In addition an experienced nurse is needed to go through the diary with the patient to ensure that they understand its contents, but this is not significantly more than might have been provided by an unstructured discussion in the past. However, compared with providing formal CBT to all patients struggling to cope with their experience this is likely to be a cost-effective therapy.
The study had a number of strengths but also limitations and possibility of bias. One of its strengths is the low attrition rate, which can be attributed to the use of research staff with previous experience of following patients up and the direct interview style method rather than using postal questionnaires. In addition the wide recruitment across 12 ICUs facilitates the generalisability of the results. It was not possible to fully blind the receipt of the diary from the investigators because patients will often mention them. However, the scoring of the PDS is complicated and in components and is therefore difficult to influence unconsciously. The interviewing investigators were kept blind to the separate symptom group scores and the overall diagnosis of PTSD. In addition the intervention patients had a discussion session with an experienced investigator to go through the diary that could have influenced the results. However, the current practice for both control and study group patients at several of the study sites was to give them verbal information about their illness prior to discharge from hospital, which would have entailed a similar discussion. This could be examined in further studies. Another possible limitation is the fact that not all patients could get back to the hospital to receive their diary or for the final interview due to travelling distance and so these interviews were conducted by telephone. This was a pragmatic study and tried to mimic what would be normally done clinically. The majority of study participants were interviewed face to face in a hospital setting so the likelihood of this having an influence on the incidence of PTSD is not great. Finally, it would have been preferable to have used the PDS at one month so that patients with previous PTSD, not related to their ICU stay, were recognised prior to randomisation and excluded. The PDS can take one hour to complete and for some patients at one month this is still too long for them to maintain concentration and give reliable information. This would also have been difficult where the interview had to be conducted by telephone. A compromise was to make the diagnosis based on the three month PDS and exclude those patients with pre-existing PTSD from the analysis.
The patients in this study reported finding both the text and the photographs helpful in understanding their illness. This is a simple and very practical intervention, which this study shows is effective in reducing the incidence of new PTSD after critical illness. The UK NICE guidelines on the treatment of PTSD suggest that targeting at-risk groups rather than blanket interventions should be practiced [12
]. This would mean that ICU patients would only receive a diary if they had high levels of symptoms. However diaries have been seen simply as a source of information for patients about their illness and it has been suggested that all patients staying on the ICU for more than 48 hours should have one [34
]. In practice their use may fall somewhere in the middle with the longer-stay patients likely to benefit the most and being an achievable target. Those patients with low levels of PTSD symptoms may still be happy to receive the information it contains. The study shows that those intervention patients scoring very highly for PTSD symptoms using the PTSS-14 got the biggest reduction in symptoms by three months, whereas the majority of those not scoring highly remained unchanged. However, this was a post-hoc
analysis resulting in a low number of patients for analysis. The fact that when all the patients were examined there was no significant difference between the two study groups in the change in PTSS-14 scores between one and three months is not surprising as only about 10% of the patients scored more than 45 on the PTSS-14 at one month and the 90% of patients with lower scores masked the result.
The lowest occurrence of new-onset PTSD in the intervention patients is an important first step in helping these patients to put their lives back together after critical illness.