TPC-Journal-V4-Issue3

The Professional Counselor \Volume 4, Issue 3 183 Spectrum Disorders and Dimensionality Both the DSM and ICD classify mental disorders into discrete categories. Clinicians make a yes-no decision about whether or not an individual has a disorder, based upon the particular criteria. But it has long been known that this categorical approach is fraught with problems (First & Westen, 2007; Widiger, 2005). First, comorbidity is common and there is some question as to whether comorbid conditions such as depression and anxiety are distinct or are really different expressions of some shared underlying dysfunction (Lilienfeld et al., 2013). Second, clinicians have used the not otherwise specified (NOS) category 30–50% of the time, indicating that a sizable proportion of phenomena have a varied presentation that existing categories do not capture (Widiger, 2005). This is problematic because NOS is not particularly informative in terms of describing the condition or making decisions about treatments. Finally, a categorical system assumes that each disorder is homogenous and that disorder occurs at the particular cut point. There is no recognition of subthreshold symptoms, and there is the assumption that those who do fulfill the criteria are qualitatively similar. This view is at odds with data showing that symptoms vary considerably in terms of severity and accompanying features (First & Tasman, 2004). In this sense, categorical assignment loses potentially useful clinical information about the condition and about what treatment strategies might be indicated. Innovation DSM-5 attempts to address this issue by introducing dimensionality to supplement the categorical approach (APA, 2013). While categories indicate differences in kind , dimensions describe variations in degree (Lilienfeld et al., 2013) . From this perspective, mental disorders are considered to lie on a continuum, like blood pressure. Theoretically, the spectrum can run from optimal functioning to significant impairment. Markers of morbidity or adverse outcome determine where on the spectrum the cut point for disorder is drawn. In the case of blood pressure, for example, it is 140/90. This dimensionality allows for more fine-grained determination of not only severity or impairment, but also improvement or deterioration. Over the past 30 years, research has shown that many mental disorders appear to be more dimensional and heterogeneous than suggested by ICD ’s or DSM ’s purely categorical system (First & Westen, 2007; Helzer, 2011; Paris, 2013). Dimensionality is incorporated into DSM-5 in three general ways. First, DSM-5 has added several formal spectrum disorders, which combine highly related disorders. Autism spectrum disorder merges together DSM- IV-TR’s autism disorder, Asperger’s disorder, childhood disintegrative disorder and pervasive developmental disorder NOS. Research has shown that these four conditions share many common symptoms, and the differences are more a matter of degree (APA, 2013; Tsai & Ghaziuddin, 2014). Another spectrum disorder is substance use disorder, which blends the former categories of abuse and dependence. The somatic spectrum is captured by somatic symptoms disorder, which merges what was formerly somatization disorder, pain disorder and undifferentiated somatoform disorder. For each of these spectrum disorders, DSM-5 provides a severity rating as well as other specifiers to note degree of impairment and complicating features. A second way that dimensionality is infused into DSM-5 is that severity ratings and an expanded list of specifiers have been placed within the existing categories. In a sense, DSM-5 tries to dimensionalize the category. While this was done to some extent in previous editions, DSM-5 broadens this effort throughout the manual. For example, a number of new specifiers were added to describe mood episodes such as anxious distress (presence of comorbid anxiety), mixed features (presence of symptoms from the opposite mood pole), and peripartum onset (onset of symptoms sometime during pregnancy through one month post-delivery). The addition of these notations can be helpful in making treatment-planning decisions (First & Tasman, 2004). For example, severity ratings are an important consideration in deciding whether to use psychotherapy or