The DSM-5 on the USMLE
THE DSM-5 ON THE USMLE: WHAT SHOULD YOU KNOW?
The American Psychiatric Association officially released its latest version of the Diagnostic and Statistical Manual of Mental Disorders, the DSM-5, in May 2013. The APA made several significant changes in to the diagnostic criteria in the DSM-5 even changed several diagnostic categories themselves. While these changes will have broad effects on the practice of psychiatry, the more immediate concern to medical students and recent medical school graduates is the effect that these changes will have on the USMLE boards.
The USMLE’s stance on the DSM-5
On November 4, 2013, the United States Medical Licensing Examination directors announced that they would be moving from the DSM-IV to the DSM-5 immediately. However, since Step 1, Step 2 CK, and Step 3 of the USMLE are each derived from a large pool of questions developed over a long period. In actuality, the transition between DSM versions will actually be far from “immediate.” In fact, the USMLE publishers acknowledge that the complete change will likely take several years.
According to sources at the USMLE, the first goal was to purge questions from the existing content pool that are based on the DSM-IV. In fact, they have insisted that any psychiatric diagnosis content not based on new, DSM-5 criteria has already been eliminated from all three steps of the USMLE. On the other hand, they admit that the transition clinical psychiatric terminology from fourth to fifth edition standards will merely begin in 2014. So it is quite possible that someone taking a USMLE exam within the next three years may be tested on questions from both the DSM-IV and DSM-5.
What is new in the DSM-5?
One of the main changes (mostly important for clinicians and those who are interested in billing for psychiatric services) is that the axis system of the DSM-IV has been largely revised. The DSM-5 now follows a multiaxial system in which diagnoses from Axis I, II, and III are all included on a single “axis” for purposes of diagnostic coding. Axis IV and Axis V, as they were known previously, have been eliminated. Clinicians now use a rubric called “dimensional assessments” to assess the severity of the particular patient’s symptoms or disorder and response to treatment. For medical students studying for the USMLE, changes in terminology will be the greatest “high yield” topics.
An example of a change in terminology is that the DSM-5 no longer uses the term mental retardation. The term mental retardation is potentially pejorative and offensive to some people. For this and other reasons, the term mental retardation has been replaced by “intellectual disability.” Intellectual disability is a condition in which deficits in cognitive ability first occur during development and are consistent with a mental disorder as defined by criteria listed in the DSM-5.
The diagnostic criteria for ADHD are largely similar in the fifth DSM version. The 18 symptoms listed in the DSM-IV are still used in the newest edition and are split into the domains of inattention and hyperactivity/impulsivity. It is now possible for patients to be diagnosed with ADHD and autism spectrum disorder at the same time. There have also been some changes with the age cutoffs—in essence, younger children need to exhibit fewer symptoms in early life in order to meet new diagnostic criteria.
The diagnostic criteria and guidelines for schizophrenia have changed rather significantly with the recent update. Because they are not useful from the diagnostic or treatment perspectives, schizophrenia subtypes (e.g., paranoid, catatonic ) have been eliminated from the new edition. Patients must exhibit at least one of the so-called positive symptoms (delusions, hallucinations, or disorganized speech) in order to qualify for a diagnosis. Also, some of the more structured requirements for hallucinations or delusions have been eliminated (e.g., bizarre delusions).
The biggest change to bipolar and related disorders is in Criterion A. Specifically, patients do not need to exhibit “classic” symptoms of major depressive episode and mania. Instead, the criteria has been “softened” a bit to include the concept of “mixed features.” Mixed features are intended to account for cases in which mania exists with only depressive features (rather than frank unipolar depression). On the other hand, it may also apply if the patient has clear depression with some manic or hypomanic behaviors.
The diagnostic criteria for major depressive episode have remained more or less identical between the two versions. Of note, the bereavement exclusion of DSM-IV has been eliminated from DSM-5. This means that prolonged bereavement now qualifies as major depression, essentially. Also added to the DSM-5 were a number of specifiers, especially for suicidal thoughts and tendencies.
Obsessive-compulsive disorder, posttraumatic stress disorder, and acute stress disorder are no longer included under the categorical umbrella of anxiety disorders. Instead, anxiety disorders are mainly limited to generalized anxiety disorder, panic disorder, phobias, and social anxiety disorder. Changes within anxiety disorders, while great in number, are not likely to be tested on the USMLE because they are somewhat subtle. That said, it is important to note that panic disorder and agoraphobia represent two separate diagnoses in the DSM-5. Moreover, patients are no longer required to recognize that their anxiety is excessive or unreasonable. The newest edition requires only that the anxiety is out of proportion to the realities of the provocative situation.
Trauma- and Stressor-Related Disorders
This category is the new home to posttraumatic stress disorder and acute stress disorder, among others. It has undergone broad changes – perhaps as dramatic as any section of the DSM. The diagnosis of acute stress disorder, for example, no longer contains some of the more restrictive stipulations of earlier versions. Patients may qualify for a diagnosis of acute stress disorder if they exhibit 9 of 14 symptoms in certain diagnostic categories.
PTSD has changed dramatically in the DSM-5. Clinicians must specifically identify if the trauma was experienced by the patient, witnessed by the patient, or in some other way in directly experienced. There are four symptom clusters rather than three, including re-experiencing, avoidance, persistent negative alterations in cognitions and mood, and arousal. Certain features of PTSD, such as irritable/aggressive behavior or reckless/self-destructive behavior, are now more prominent among the diagnostic criteria for PTSD.
Students who are planning on taking the USMLE will need to consider how to study for the psychiatric portion of the test. The makers of the USM LE have attempted to adapt to the newest edition of the DSM, but these changes will take time. Therefore, examinees should focus on the high-yield changes listed in this article. The highest yield material are changes in terminology that appear in the DSM-5. Because the questions may still come up in an actual examination, students should also recall what these terms meant in the DSM-IV. While diagnostic criteria are different in the DSM-5, especially for disorders such as PTSD, most of the questions included on the USM LE will not drill down to this level of detail. On the other hand, top students will be aware of the key changes that were made to the DSM in the most recent update and be able to answer questions based on the DSM-5.
Vincent Stevenson is the creator of Scrub Wars (scrubwars.com and @scrubwarsapp), an innovative medical gaming app targeting the USMLE Step I and COMLEX Level I exams.Share