Differential Diagnosis – Dysthymic Disorder vs. Major Depressive Disorder


The differential diagnosis of Dysthymic Disorder (DD, also known as depressive neurosis, minor depression disorder, or neurotic depression) and Major Depressive Disorder (MDD) is made difficult because they share the same symptom constellations.  The word ‘Dysthymic’ is of Greek origin, literally translating into “resembling a bad (or abnormal) spirit.”  (Colman, 2009, p. 234)  “In Major Depressive Disorder (MDD), the depressed mood must be present for most of the day, nearly every day, for a period of at least 2 weeks, whereas Dysthymic Disorder (DD) must be present for more days than not over a period of at least 2 years.”  (American Psychiatric Association, Diagnostic and statistical manual of mental disorders, 2000, p. 374)  Thus, we can visualize DD as a chronic, yet less severe type of depression that typically persists for many years.  Clients with DD may report that they do not recall being depressed and they may lead fully functional lives… as a result, it may be exceedingly difficult to distinguish DD from the client’s usual functioning or personality type.  The bottom line is that the onset, persistence, and severity of depression episodes are not easily evaluated retrospectively.

The DSM-IV-TR, the diagnostic tool of choice for clinicians, sums up differential diagnosis best.  “If the initial onset of chronic depressive symptoms is of sufficient severity and number to meet the full criteria for a Major Depressive Episode, the diagnosis would be Major Depressive Disorder, Chronic (if the full criteria are still met, or Major Depressive Disorder, In Partial Remission (if the full criteria are no longer met).  The diagnosis of DD can be made following MDD only if the DD was established prior to the first Major Depressive Episode (i.e., no Major Depressive Episodes during the first 2 years of dysthymic symptoms), or if there has been a full remission of the MDD lasting (i.e., lasting at least 2 months) before the onset of the DD.”  (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000, p. 379)

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This distinction is further complicated by the diagnoses of mood disorder due to a general medical condition and substance-induced mood disorders, both of which are rather self explanatory.  It is also worth noting that depressive symptoms are frequently associated with chronic Psychotic Disorders like Schizophrenia and Schizoaffective Disorder.  A separate diagnosis of DD is not made of the symptoms occur exclusively during the course of the Psychotic Disorder.  (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000, p. 380)

Beyond the typical differential diagnosis techniques, some have suggested that Axis II personality dimensions (PDs) can be utilized in the differential diagnosis of Axis I Depression disorders.  “Personality dimensions are on the forefront of discussions regarding how to improve diagnostic clarification, and may provide a useful way in which to understand and model the comorbidities among and between Axis I and II conditions.”  (Bagby, Quilty, & Ryder, 2008, expression Conclusions)  Not only can PDs have significant impact on the diagnosis process, but they can dramatically alter the course of treatment.  For example, Bagby and associates (2008) found that neurotic personalities respond better to pharmacotherapy when compared to psychotherapy.  Inevitably, to be effective at diagnosis and treatment, we need to consider more than just the DSM-IV-TR… we need to individualize treatment plans based on a true representation of the individual client.  That representation, in my opinion, must include the underlying PDs that compose the fabric of the human experience.

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References

American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.). Washington, DC: Author.

Bagby, R. M., Quilty, L. C., & Ryder, A. C. (2008, Jan). Personality and depression. Canadian Journal of Psychiatry, 53(1), 14-26. Retrieved from http://ezproxy.bellevue.edu:80/login?url=http://proquest.umi.com.ezproxy.bellevue.edu/pqdweb?did=1426048691&sid=4&Fmt=3&clientId=4683&RQT=309&VName=PQD

Colman, A. M. (2009). Oxford dictionary of psychology (3rd ed.). Oxford, NY: Oxford University Press.

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