International Society for Traumatic Stress Studies

Congratulations to the DSM-V Student Essay Contest Winner: Erika Wolf of Boston University

Posted 1 September 2008 in StressPoints by ISTSS

The ISTSS Student Essay Contest asked students to identify an issue that is important for DSM-V to address, to identify why this was an important issue and offer suggestions for how DSM-V could improve on DSM-IV to address this issue.

Congratulations to winning essayist, Erika Wolf of Boston University.Second place was awarded to Paul Frewen of the University of Western Ontario. Third place was given to Laurie Burke of the University of Memphis. More than 50 student essays were received. Essays were reviewed by an ISTSS committee including clinicians, researchers, and journalists. All three winners have received funding to attend the 2008 ISTSS meeting in Chicago where they will be presented with their awards.  

ISTSS would like to thank all student participants and to acknowledge the Dart Center for Journalism and Trauma and the Dart Foundation for their generous support of the contest.

 
First-Place Essay by Erika Wolf, Boston University

To the DSM-V Committee:

As you grapple with the difficult task of refining our conceptualization, nomenclature, and description of psychiatric morbidity, I would like to suggest that the Committee focus on ensuring that the diagnostic criteria for psychiatric disorders reflects what we know about the structure of common mental disorders and their inter-relatedness. In this letter I will briefly review research examining the structure of psychopathology, discuss the importance of refining our conceptualization of posttraumatic stress disorder (PTSD), and propose a new, empirically-based organization for one spectrum of DSM-V disorders that would better reflect their underlying structure and inter-relations.

Following the medical model, DSM has historically treated mental disorders as discrete categorical entities. Overwhelmingly, however, research suggests that psychopathology is dimensional (i.e., psychopathological traits are extreme presentations of normal-range ones and continuously distributed) not categorical, with overlapping symptoms across disorders originating from a shared (not disorder-specific) basic structure. Specifically, research suggests that the anxiety and unipolar mood disorders—the internalizing disorders, also referred to as the “distress” (Clark & Watson, 1991; Mineka et al., 1998)  or “emotional” (Watson, 2005) disorders—are rooted in a common underlying structure (cf, Achenbach & Edelbrock, 1978, 1984, Krueger, 1999). What is common to these disorders is a core individual tendency towards negative mood and affect which puts one at risk, generally, for any disorder in this class (Brown et al., 1998; Krueger et al., 2001; Mineka et al., 1998; Watson, 2005). These disorders are also defined by symptoms that are disorder-specific (Brown et al., 1998; Mineka et al., 1998; Watson, 2005). However, the DSM does not distinguish between the common and disorder-specific symptoms—all symptoms are weighted equally and common symptoms are repeated across disorders—this limits the discriminant validity of the diagnoses and complicates diagnostic assessment.

Symptoms shared with other disorders are a particular problem for PTSD, which has criteria overlap with depression and GAD (and, to a lesser extent, with panic disorder and specific phobia). PTSD evidences very high rates of comorbidity: nearly 50% of individuals with the disorder exhibit three or more co-occurring disorders (Kessler et al., 1995). It has a strong common-factor component, with 8 out of 17 symptoms reflecting non-PTSD-specific distress (Simms et al., 2002). Specifically, criteria C3-C7 (emotional numbing) and D1-D3 (sleep disturbance, anger, and concentration problems) reflect the dysphoria and negative emotionality common to internalizing disorders while the B symptoms (reexperiencing), and criteria C1-C2 (avoidance) and D4-D5 (hypervigilence and startle) are relatively PTSD-specific (Simms et al., 2002). This does not mean that negative mood and affect are not part of the clinical presentation of PTSD, but that they are not specific to the diagnosis; retaining them complicates differential diagnosis and makes it difficult to study PTSD-specific phenomena.

Unlike the DSM classification system, the system for classifying living organisms—the taxonometric organization of species—delineates what is common and unique to all things living. For example, monkeys, apes, and humans belong to the primate order due to their shared characteristics (e.g., forward facing eyes, grasping fingers), but they are distinguished from one another by specific characteristics (e.g., shape of spine and forehead) and therefore, belong to different genus and species classifications. This system elegantly defines these boundaries while still documenting relatedness and common origins. I believe a similar approach could be applied to our observations about the nature of internalizing disorders.

The aim of my proposal is to clarify the boundaries between PTSD and related disorders so as to increase the distinctiveness of the disorder while still capturing the symptoms of negative emotionality that pervade the internalizing disorders. My proposal is to remove all common-factor symptoms from disorder-specific criteria and move them onto a separate common criterion that would be necessary for all internalizing diagnoses, but not sufficient for any specific one. This criterion would be analogous to the higher-order classifications in the taxonomy of living organisms as it would reflect shared internalizing disorder attributes. It would be used to reflect the severity of psychopathology and would be reported once in the diagnostic profile, along with specific diagnoses (e.g., Diagnostic Profile: PTSD and GAD; Common-factor Severity Score: 6/13). The common-factor symptoms include: depressed mood, anxiety, anhedonia, social isolation, irritability/anger, sleep and appetite disturbances, concentration problems, guilt, worthlessness, shame, hopelessness, and excessive worry/rumination.

The PTSD-specific criteria, akin to lower-order species-defining classifications, include (the number of Criterion B-D symptoms required would be determined through field tests):

A. Exposure to a Traumatic Event
B. Reexperiencing of the Traumatic Event:
B1. Recurrent and intrusive recollections of the event
B2. Recurrent distressing dreams of the event
B3. Reliving of the event/flashbacks
B4. Intense psychological distress at exposure to internal or external trauma-cues
B5. Physiological reactivity at exposure to internal or external trauma-cues
C. Avoidance of Stimuli Associated with the Trauma:
      C1. Efforts to avoid thoughts, feelings or conversations associated with the trauma
      C2. Efforts to avoid activities, places, or people associated with the trauma
D. Hyperarousal:
      D1. Hypervigilance
      D2. Exaggerated startle response

This same approach would be applied to redefine the criteria for the remaining internalizing disorders so that the individual disorder criteria would reflect only what is specific to that disorder while common-factor symptoms would be captured just once, on the Severity Dimension.

The advantages of discriminating between common and disorder-specific symptoms include: a) incorporating dimensionality into the DSM while still allowing for categorical diagnoses; b) reducing comorbidity; c) increasing statistical power to detect correlates (e.g., genes, biomarkers, brain activity) of the common versus disorder-specific factors; d) increasing collaboration across camps of disorder-specific researchers and clinicians; e) allowing for examination of therapies appropriate across internalizing disorders versus those with specificity for individual disorders; and f) providing a parsimonious conceptualization of the internalizing disorders that is rooted in theory, empirical research, and clinical observation. Just as the classification system for living organisms describes what we know about individual species and about groups of related species by observing nature and discerning its boundaries and areas of overlap, so too should our system of classifying psychological phenomena reflect the natural world.

 
Sincerely,
Erika Wolf
 
 
References

Achenbach, T. M. & Edelbrock, C. S. (1978). The classification of child psychopathology: A review and analysis of empirical efforts. Psychological Bulletin, 85, 1275-1301.
Achenbach, T. M. & Edelbrock, C. S. (1984). Psychopathology of childhood. Annual Review of Psychology, 35, 227-256.
Brown, T. A., Chorpita, B. F., & Barlow, D. H. (1998). Structural relationships among dimensions of the DSM-IV anxiety and mood disorders and dimensions of negative affect, positive affect, and autonomic arousal. Journal of Abnormal Psychology, 107, 179-192.
Clark, L. A., & Watson, D. (1991). Tripartite model of anxiety and depression:
Psychometric evidence and taxonomic implications. Journal of Abnormal Psychology,100, 316-336.
Kessler, R. C., Sonnega, A., Bromet, E., Hughes, M., & Nelson, C. B. (1995). Posttraumatic stress disorder in the National Comorbidity Survey. Archives of General Psychiatry, 52, 1048-1060.
Krueger, R. F. (1999). The structure of common mental disorders. Archives of General Psychiatry, 56, 921-926.
Krueger, R. F., McGue, M., & Iacono, W. G. (2001). The higher-order structure of common DSM mental disorders: Internalization, externalization, and their connections to personality. Personality & Individual Differences, 30, 1245-1259.
Mineka, S., Watson, D., & Clark, L. A. (1998). Comorbidity of anxiety and unipolar mood disorders. Annual Review of Psychology, 49, 377-412.
Simms, L. J., Watson, D., & Doebbeling, B. N. (2002). Confirmatory factor analyses of posttraumatic stress symptoms in deployed and nondeployed veterans of the Gulf War. Journal of Abnormal Psychology, 111, 637-647.
Watson, D. (2005). Rethinking the mood and anxiety disorders: A quantitative hierarchical model for DSM-V. Journal of Abnormal Psychology, 114, 522-536.