Diagnostic Criteria and Characteristics
Post-traumatic stress disorder (PTSD) was initially characterized as an anxiety disorder that developed in response to a severe trauma in which an individual experienced, witnessed, or was confronted by actual or threatened death, injury, or loss of physical integrity of self or others. The Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), stipulated for the first time that being diagnosed with a life-threatening illness or learning that one's child had such an illness qualifies as a stressful event.
In 1994, the application of PTSD to patients with cancer began with the redefinition of the trauma criteria in the DSM-IV to include life-threatening illness. The essential feature of this disorder is the development of characteristic symptoms following exposure to an extreme traumatic stressor. These events elicit responses of intense fear, helplessness, or horror and trigger three clusters of PTSD symptoms. Symptoms from each of the following three clusters must be present for an individual to meet the full criteria for a diagnosis of PTSD:
- Reexperiencing the trauma (nightmares, flashbacks, and intrusive thoughts).
- Persistent avoidance of reminders of the trauma (avoidance of situations, numbing of general responsiveness, and restricted range of affect).
- Persistent increased arousal (sleep difficulties, hypervigilance, and irritability).
These symptoms must last for at least 1 month and cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
Symptoms that last for at least 1 day but less than 1 month and that cause significant distress or impairment in social, occupational, or other important areas of functioning might meet the diagnostic criteria for Acute Stress Disorder (ASD). ASD is often a prodrome to PTSD.
The Conceptual Fit of PTSD and Cancer
Conceptual and practical problems can arise in the application of PTSD to cancer patients and survivors. The basic concept of an extreme traumatic stressor has been described variously as an event involving direct personal experience that involves actual or threatened death or serious injury. This event can be protracted and continuous but is more frequently a single, time-limited event (e.g., rape, natural disaster). In this context, for the person who has experienced a diagnosis of cancer, the exact nature of the trauma is unclear. Is it the actual diagnosis, aspects of the treatment process, information given about recurrence, negative test results, or some other aspect of the cancer experience? Identifying a discrete stressor within the multiple crises that constitute a cancer experience is much more difficult than it is for other traumas. In one study of breast cancer patients  who underwent autologous bone marrow transplant, more PTSD-like symptoms were reported at the time of initial diagnosis.
Another concern regarding conceptual fit is related to reexperiencing the trauma. Diagnostic criteria B require persistent reexperiencing of the traumatic event, implying that the patient would first encounter a trauma and then, at a later time, reexperience it in various ways. In a study of women with early-stage breast cancer, however, researchers  found that the traumatizing aspects of the cancer experience were receiving the diagnosis and waiting for test results from node dissection. Arguing that these “information traumas” are future oriented and tend to cause intrusive worry about the future—not intrusive recollections of past events—the authors questioned whether cancer fits a conceptual model of PTSD trauma. Reexperiencing the trauma is often measured in terms of unwanted intrusive thoughts of the traumatic event. The cognitive processing of a current and ongoing health threat with uncertain outcome might differ significantly from unwanted intrusive thoughts about a single past event. Some researchers have argued that not all intrusive thoughts are negative or indicate reexperiencing a trauma, but rather that they might represent appropriate vigilance and attention to potential symptoms that could result in appropriate help-seeking.[5,6]
Conversely, a unique study assessing the physiological reactivity of breast cancer patients to a personalized imagery script of their most stressful experiences with breast cancer found elevated physiologic responses that were comparable to those of PTSD patients who had experienced other (noncancer-related) traumas. This finding suggests a good fit between cancer patients and the PTSD trauma model, as it shows comparable symptoms of increased arousal in cancer patients. Also, in a factor analytic study  designed to confirm the presence of the three broad PTSD symptom clusters (reexperiencing, avoidance of reminders, and hyperarousal), researchers found some tentative support for the DSM-IV symptom clusters in a sample of breast cancer survivors.
In a study of 74 women breast cancer survivors interviewed at 18 months postdiagnosis via the Structured Clinical Interview for DSM (SCID), three groups were identified: one meeting the full criteria for PTSD (n = 12), another meeting partial but not full criteria for PTSD (i.e., subsyndromal, n = 5), and a no-PTSD group (n = 47). Further analyses investigated group differences. Some notable differences between the full-criteria PTSD group and the subsyndromal group include a significantly higher number of violent traumas (e.g., physical abuse, rape) and a higher number of anxiety disorders prior to a cancer diagnosis among the full-criteria PTSD group.
The PTSD group was also found to have more advanced disease (75% stage III vs. 7% in the subsyndromal group and 6% in the no-PTSD group), more extensive surgeries (83% modified radical mastectomy vs. 47% in the subsyndromal group and 38% in the no-PTSD group), and a higher lifetime prevalence of prior PTSD (42%) than the subsyndromal group (7%) and the no-PTSD group (9%).
Further research will be needed to continue to investigate the important question of how well the conceptual model of PTSD as an anxiety response to a major life trauma fits the life experience of patients with cancer. Reviews have argued both in favor of  and against  the continued use of trauma models for conceptualizing the experience of cancer. Others have proposed alternate conceptual models.[5,10]
- American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders: DSM-IV. 4th ed. Washington, DC: American Psychiatric Association, 1994.
- American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders: DSM-IV-TR. 4th rev. ed. Washington, DC: American Psychiatric Association, 2000.
- Mundy EA, Blanchard EB, Cirenza E, et al.: Posttraumatic stress disorder in breast cancer patients following autologous bone marrow transplantation or conventional cancer treatments. Behav Res Ther 38 (10): 1015-27, 2000. [PUBMED Abstract]
- Green BL, Rowland JH, Krupnick JL, et al.: Prevalence of posttraumatic stress disorder in women with breast cancer. Psychosomatics 39 (2): 102-11, 1998. [PUBMED Abstract]
- Deimling GT, Kahana B, Bowman KF, et al.: Cancer survivorship and psychological distress in later life. Psychooncology 11 (6): 479-94, 2002 Nov-Dec. [PUBMED Abstract]
- Palmer SC, Kagee A, Coyne JC, et al.: Experience of trauma, distress, and posttraumatic stress disorder among breast cancer patients. Psychosom Med 66 (2): 258-64, 2004 Mar-Apr. [PUBMED Abstract]
- Cordova MJ, Studts JL, Hann DM, et al.: Symptom structure of PTSD following breast cancer. J Trauma Stress 13 (2): 301-19, 2000. [PUBMED Abstract]
- Shelby RA, Golden-Kreutz DM, Andersen BL: PTSD diagnoses, subsyndromal symptoms, and comorbidities contribute to impairments for breast cancer survivors. J Trauma Stress 21 (2): 165-72, 2008. [PUBMED Abstract]
- Gurevich M, Devins GM, Rodin GM: Stress response syndromes and cancer: conceptual and assessment issues. Psychosomatics 43 (4): 259-81, 2002 Jul-Aug. [PUBMED Abstract]
- Cordova MJ, Andrykowski MA: Responses to cancer diagnosis and treatment: posttraumatic stress and posttraumatic growth. Semin Clin Neuropsychiatry 8 (4): 286-96, 2003. [PUBMED Abstract]