Comorbidity

A timely and careful assessment of cancer patients is critical to identify the symptoms of post-traumatic stress disorder (PTSD), to note the deleterious impact of the symptoms on functioning, and to plan interventions targeted at the most distressing symptoms. It is also critical that the assessment distinguishes between the full DSM-IV PTSD syndrome (meets all required diagnostic criteria) and PTSD-related symptoms only.

The most difficult aspect of PTSD assessment in the cancer setting is the determination of precisely when to evaluate the patient. Diagnosis is complicated because cancer is not an acute or discrete event, but is an experience marked by repeated traumas and indeterminate length. Thus, an individual may exhibit the symptoms of PTSD at any point from diagnosis through treatment, to treatment completion and, possibly, to recurrence.[1] Patients such as Holocaust survivors whose history of victimization causes PTSD or its symptoms can have the symptoms activated by any number of stimuli encountered during their treatment (e.g., clinical procedures such as being inside magnetic resonance imaging or computed tomography scanners). While such patients may have more difficulty in adjusting to cancer and cancer treatment, their PTSD symptomatology is likely to vary greatly according to their circumstances. The relative predominance of specific PTSD symptoms may wax and wane throughout the cancer experience and beyond.[2]

The definition in the DSM-IV indicates that although PTSD symptoms usually begin within the first 3 months after trauma, there may be a delay of months or even years before symptoms appear.[2,3] These findings support the necessity for long-term monitoring of survivors of cancer and their family members.

At least one study found that individuals who have experienced a traumatic event may exhibit early symptoms without meeting the full criteria for a diagnosis of PTSD.[4] Nonetheless, the appearance of these early symptoms was found to predict later development of full PTSD syndrome. These results lend further credence to the need for both repeated and long-term follow-up of individuals exposed to the trauma of cancer. (Refer to the PDQ summary on Normal Adjustment and the Adjustment Disorders for further information.)

The difficulty in properly diagnosing PTSD may be compounded by the overlapping of PTSD symptoms with those of other psychiatric disorders and by the time-related aspects of normal adjustment. For example, irritability, poor concentration, hypervigilance, excessive fear, and disturbed sleep are also symptoms of generalized anxiety disorder. Other arousal and avoidance symptoms are common to PTSD, phobias, and panic disorder, but loss of interest, sense of a foreshortened future, avoidance of other people, and sleep impairment might suggest both PTSD and depressive disorders. Even normal reactions to the diagnosis and treatment of life-threatening disease can consist of responses such as intrusive thoughts, disassociation and depersonalization, sleep disturbances, and heightened arousal. Therefore, clinicians and researchers must be particularly attuned to the causes, duration, and severity of PTSD-like symptoms when considering PTSD among several diagnoses. For instance, in a study of women with breast cancer, 41% reported experiencing “intense fear, helplessness, or horror” (DSM-IV PTSD diagnostic criterion A2); however, on further comprehensive diagnostic interview, only 4% met the full PTSD criteria. Assessment must be able to distinguish between general psychological distress and symptoms of PTSD.[5]

The accurate diagnosis of PTSD also requires the use of reliable and valid instruments. Many studies have used the PTSD module of the Structured Clinical Interview for DSM-III-R–Nonpatient Edition (SCID-NP).[6] This is a clinician-administered, structured clinical interview that is time intensive and may not be feasible in settings without adequately trained mental health professionals. However, one study [7] investigated the utility of a cost-effective screening tool, the PTSD Checklist-Civilian Version (PCL-C).[8] In this study of 82 women diagnosed with breast cancer assessed 6 to 72 months after cancer treatment, use of the PCL-C resulted in a sensitivity of .60 and specificity of .99. Other cutoff scores for the PCL-C that could be used were discussed, depending on the clinical resources available in specific cancer treatment settings. Most research studies have used the Impact of Event Scale, a self-report of intrusive thoughts;[9] however, it is important to note that this is not designed to be an assessment procedure for PTSD.

In attempting to diagnose PTSD, it is important to be aware that this disorder is often marked by comorbid psychopathology. Substance abuse, affective disorders, and other anxiety disorders are consistently encountered in samples of people with PTSD.[2,10-12] It has been reported that war veterans with PTSD exhibited substantial comorbid pathology that included major depression (32% to 72%), alcohol dependence (65%), drug dependence (40%), social phobia (50%), and obsessive-compulsive disorder (10%).[13] High rates of concurrent disorders have also been documented in other trauma victims. For example, 40% to 42% of disaster survivors with PTSD also qualified for a diagnosis of major depression, and 20% to 42% met the criteria for concurrent generalized anxiety disorder.[13,14] While this has not yet been studied in cancer patients or survivors, the presence of co-occurring psychiatric disorders in Vietnam War veterans and other trauma victims would indicate that cancer clinicians should be alert to the need to identify and treat such related syndromes in their patients.

References

1. Greenberg DB, Goorin A, Gebhardt MC, et al.: Quality of life in osteosarcoma survivors. Oncology (Huntingt) 8 (11): 19-25; discussion 25-6, 32, 35, 1994.  [PUBMED Abstract]
   
   
2. American Psychiatric Association.: Diagnostic and Statistical Manual of Mental Disorders: DSM-IV. 4th ed. Washington, DC: American Psychiatric Association, 1994. 
   
   
3. Solomon Z, Garb R, Bleich A, et al.: Reactivation of combat-related posttraumatic stress disorder. Am J Psychiatry 144 (1): 51-5, 1987.  [PUBMED Abstract]
   
   
4. Perry S, Difede J, Musngi G, et al.: Predictors of posttraumatic stress disorder after burn injury. Am J Psychiatry 149 (7): 931-5, 1992.  [PUBMED Abstract]
   
   
5. 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]
   
   
6. Spitzer RL, Williams JB, Gibbon M, et al.: The Structured Clinical Interview for DSM-III-R (SCID). I: History, rationale, and description. Arch Gen Psychiatry 49 (8): 624-9, 1992.  [PUBMED Abstract]
   
   
7. Andrykowski MA, Cordova MJ, Studts JL, et al.: Posttraumatic stress disorder after treatment for breast cancer: prevalence of diagnosis and use of the PTSD Checklist-Civilian Version (PCL-C) as a screening instrument. J Consult Clin Psychol 66 (3): 586-90, 1998.  [PUBMED Abstract]
   
   
8. Weathers FW, Huska JA, Keane TM: PCL-C for DSM-IV. Boston, Mass: National Center for PTSD-Behavioral Science Division, 1991. 
   
   
9. Sundin EC, Horowitz MJ: Impact of Event Scale: psychometric properties. Br J Psychiatry 180: 205-9, 2002.  [PUBMED Abstract]
   
   
10. Rundell JR, Ursano RJ, Holloway HC, et al.: Psychiatric responses to trauma. Hosp Community Psychiatry 40 (1): 68-74, 1989.  [PUBMED Abstract]
    
    
11. Davidson JR, Foa EB: Diagnostic issues in posttraumatic stress disorder: considerations for the DSM-IV. J Abnorm Psychol 100 (3): 346-55, 1991.  [PUBMED Abstract]
    
    
12. Green BL, Lindy JD, Grace MC: Posttraumatic stress disorder. Toward DSM-IV. J Nerv Ment Dis 173 (7): 406-11, 1985.  [PUBMED Abstract]
    
    
13. Keane TM, Wolfe J: Comorbidity in post-traumatic stress disorder: an analysis of community and clinical studies. J Appl Soc Psychol 20(21): 1776-1788, 1990. 
    
    
14. Smith EM, North CS, McCool RE, et al.: Acute postdisaster psychiatric disorders: identification of persons at risk. Am J Psychiatry 147 (2): 202-6, 1990.  [PUBMED Abstract]
    
    

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