Posttraumatic stress disorder (PTSD) in survivors of Hodgkin's lymphoma: prevalence of PTSD and partial PTSD compared with sibling controls

A diagnosis of cancer is a universally stressful event, and studies on the impact of cancer on psychological well-being have described common challenges experienced during treatment and in the survivorship period.[1–3] While it is recognized that for a number of cancer survivors psychological late-effects may persist even years after treatment completion, it remains unclear how commonly these late-effects take the form of Posttraumatic Stress Disorder (PTSD), and how applicable this construct is for capturing the psychological experience of cancer survivors. PTSD is a psychiatric diagnosis characterized by the development of re-experiencing, avoidance, and increased arousal symptoms following exposure to a traumatic event.[4] For over a decade, researchers have conducted empirical studies to understand the experience of cancer survivors who report symptoms consistent with PTSD. The results of these efforts have been inconsistent with wide variations in prevalence rates ranging from 3–32%, variability likely due to differences in sample characteristics, definitions and diagnostic tools across studies.[5, 6] In the adult cancer literature, most of the studies on PTSD have been conducted with survivors of breast cancer [7–15] making it difficult to generalize to males and to survivors of other diseases. In both the pediatric and adult cancer literatures, investigators interested in understanding the specific effects of cancer on the development of PTSD have tended to ask study participants to report only on the extent to which cancer has caused later PTSD symptoms, making it difficult to quantify the effects of other traumatic events or to even determine if the cancer itself was perceived as traumatic by the survivor [5, 6, 16, 17]. In addition, not all studies have included an adequate comparison group. [5, 6] Conceptually, most experts consider a cancer diagnosis to be a stressor capable of initiating the development of PTSD, a position reflected in current diagnostic criteria that include life-threatening illnesses as qualifying stressors for PTSD.[4, 6, 18] Despite this, some experts argue that cancer is too variable and complex an experience to meet criteria as a single stressor consistent with the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) standards,[4] and that the cancer experience is too different from other stressors such as combat or rape to be properly included in the PTSD criteria as it was originally intended.[5] Of relevance to this debate is the fact that the number of cancer survivors meeting diagnostic criteria for PTSD is often reported to be low.[5, 7–9, 16, 17, 19, 20] Some of these same studies, however, document a significant proportion of survivors who report severe PTSD symptoms even when they do not meet full diagnostic criteria. [7–9, 21, 22] To date, few studies have directly examined the clinical significance of these “partial-PTSD” symptoms making it difficult to determine how significantly they affect survivors’ emotional well-being. As studies explore the important question of understanding partial-PTSD in survivors, we believe this is a key question that can be addressed by directly assessing the functional impairment associated with these sub-threshold symptoms. In the present study, we attempt to contribute to the clarification of these controversial questions by addressing several issues. First, we investigate symptoms of PTSD in a cohort of long-term survivors of Hodgkin’s Lymphoma (HL), a cancer diagnosis not commonly reflected in previous PTSD research. Because HL is diagnosed at different ages, is highly curable even in advanced stages, and is diagnosed in both sexes, HL survivors represent a particularly diverse group of cancer survivors with regard to age at diagnosis, gender and intensity of treatment. Second, we compare the prevalence of PTSD in these HL survivors to a cancer-free group, namely a group of cancer-free siblings of the HL survivors recruited to the study. Finally, we address the question of partial-PTSD as a clinically relevant construct for cancer survivors, by determining if partial-PTSD is present at a significantly higher rate in survivors than in cancer-free siblings, and by assessing the number of HL survivors who experience impairment of function secondary to partial-PTSD symptomatology. We hypothesized that: 1) HL survivors will report a higher prevalence of PTSD, and partial-PTSD, than their cancer-free siblings, 2) higher rates of PTSD and partial-PTSD will be found in both male and female survivors compared to cancer-free siblings, and 3) partial-PTSD will be associated with significant impairment of functioning supporting the clinical relevance of partial-PTSD in cancer survivors.