Mapping DSM criteria onto cancer survivorship
The challenges associated with measuring posttraumatic stress responses in AYA cancer survivors are not limited to the conceptualization of trauma. Further compromising estimates of posttraumatic stress prevalence among this population is the applicability of the DSM-IV PTSD symptom classification to AYA cancer survivorship.
To meet the criteria for a diagnosis of PTSD, an AYA survivor must demonstrate a response to the traumatic event, which is characterized by three symptom clusters (Table 1).
In studies where the traumatic event is assumed to be cancer, research procedures may unintentionally prime participating survivors to view their cancer experience as traumatic, thereby creating a “focusing illusion” and risking potential bias in ascertaining prevalence estimates.55
Even in cases where the cancer experience is objectively reported as a traumatic stressor, survivors may or may not endorse symptom criteria because of confounding effects of cancer therapy (eg, late effects).
These late effects, commonly associated with cancer survivorship, are not filtered by the diagnostic criteria and have the potential to result in false positives (or false negatives) when assessing prevalence.
For example, criterion B requires re-experiencing of the traumatic event via one of the following: intrusive recollections; distressing dreams; reliving the event; or triggered psychological or physiological distress.7 It is not unusual for AYA cancer survivors to face realistic risks of relapse and/or other health-compromising morbidities. Re-experiencing or intrusion symptoms may, in their case, reflect well-founded fears about current or future health.21,57
Criterion C requires persistent avoidance of stimuli associated with the trauma and numbing of general responsiveness via at least three of the following: effortful avoidance of thoughts, feeling, or anything associated with the trauma; inability to recall aspects of the trauma; social withdrawal; emotional numbing; and a sense of a foreshortened future.7
In the case of AYA cancer survivors, traditional avoidant responses may be rare, as survivors are confronting their health realities regularly through long-term follow-up care. Withdrawal from social interaction and other activities may be more a function of developmental or psychosocial sequelae than psychological avoidance. Diminished recall may have less to do with trauma and may instead represent symptoms of long-term cognitive impairment.21
Having a sense of foreshortened future may also reflect the very real possibility of relapse rather than a traumatic stress response; unlike other traumatic stressors, cancer is an ongoing event with no clear, temporal end. The final symptom cluster, criterion D, requires persistent, increased arousal via at least two of the following: insomnia; irritability; concentration difficulties; hypervigilance; and an exaggerated startle response.7
Distinguishing between common late effects and PTSD symptoms, such as insomnia or delayed sleep onset, and concentration difficulty may prove rather difficult, as these responses also resemble the neurocognitive deficits attributed to cancer therapy.57
Criteria E and F require that these symptoms persist at least 1 month following exposure to the traumatic event, and that they significantly impair the individual’s day-to-day functioning, respectively. Given the nature of cancer’s late effects, survivors who experience symptoms are likely to have them persist beyond the 1-month mark.2
Similarly, depending on the treatment and late effects endured by survivors, daily functioning may or may not be impaired. A fourth symptom cluster has been added to the PTSD diagnostic criteria for DSM-5 (Table 3), requiring negative alterations in cognitions and mood associated with the traumatic event.15
A diagnosis of PTSD necessitates experiencing at least two of the following symptoms: inability to remember an important aspect of the trauma; persistent and exaggerated negative beliefs about oneself; persistent and disordered cognitions about the cause or consequences of the trauma leading to blame; persistent negative emotional state; diminished interest in activities; interpersonal detachment; and a persistent inability to experience positive emotions.15
Although this latest version of the DSM includes a catch-all stipulation (criterion H) stating that disturbances must not be attributable to the physiological effects of medication or a medical condition, it is not clear whether late effects of cancer necessarily exempt survivors from symptom endorsement.
Given that cancer survivors demonstrate higher levels of cognitive impairment63–68 and depressive symptoms than controls,69–73 and that a cancer diagnosis can alter one’s worldview and challenge existing schemas about the world, looking forward, clinicians, instrument developers, and researchers should take care to disentangle PTSD symptom endorsement from expected, therapy-related effects.