DSM-5-TR for the exam: the diagnoses that appear, and the details that decide them.
Duration criteria, rule-outs, and the specifiers that separate near neighbors. What to memorize and what to let go.
By Dr. Andrew Wichterman · September 15, 2026 · 7 min read · Updated October 4, 2026
You do not need the whole DSM-5-TR for either exam. You need the disorders that appear in clinical mental health practice most often, and for each one you need the duration threshold, the defining feature, and the nearest look-alike. The NCMHCE tests this inside case studies; the NCE tests it in single items under the clinical focus area.
Durations to know cold
- Major depressive episode: two weeks, with depressed mood or anhedonia plus four more symptoms.
- Persistent depressive disorder: two years in adults, one year in children and adolescents.
- Manic episode: one week (or any duration if hospitalized); hypomanic episode: four days.
- Generalized anxiety disorder: six months of excessive worry, more days than not.
- Panic disorder: recurrent unexpected attacks plus one month of worry or behavior change.
- Acute stress disorder: three days to one month after trauma. PTSD: more than one month.
- Adjustment disorder: onset within three months of a stressor, resolves within six months of the stressor ending.
- Schizophrenia: six months including one month of active symptoms. Schizophreniform: one to six months. Brief psychotic disorder: one day to one month.
- Cyclothymic disorder: two years (one in youth) of hypomanic and depressive symptoms not meeting full episode criteria.
- Insomnia disorder: three nights a week for three months.
Rule-outs the case wants you to check
- Substances and medications. Almost every case includes alcohol, cannabis, stimulants or a new prescription. If symptoms began with the substance, the exam wants substance-induced or "rule out substance" before a primary diagnosis.
- Medical conditions. Thyroid disease, head injury, sleep apnea. If the case mentions no recent physical, the right early step is a referral for medical evaluation.
- Bereavement and normal reactions. Prolonged grief disorder now exists (twelve months in adults), but ordinary grief is not a disorder.
- A bipolar history. Before diagnosing unipolar depression, the case expects you to have asked about past manic or hypomanic episodes.
Near neighbors
- Bipolar I versus bipolar II: a full manic episode versus hypomania plus major depression.
- Social anxiety disorder versus avoidant personality disorder: the latter is pervasive and begins by early adulthood.
- OCD versus OCPD: the former has obsessions and compulsions experienced as intrusive; the latter is a personality pattern the person often endorses.
- ADHD versus anxiety versus mania in children: check onset before age twelve and cross-setting impairment for ADHD.
- Schizoaffective disorder: psychosis for at least two weeks without mood symptoms, within an illness that is mostly mood episodes.
- Borderline versus bipolar: rapid mood shifts over hours tied to interpersonal triggers versus sustained episodes lasting days.
Specifiers and other things that get asked
With anxious distress, with mixed features, with peripartum onset, with seasonal pattern. Severity levels. The trauma criteria in PTSD (intrusion, avoidance, negative alterations in cognition and mood, alterations in arousal). The change from Roman numerals to Arabic in the DSM-5, and the removal of the multiaxial system. Neurodevelopmental disorders are diagnosed in children but persist. Know the WHODAS and the cross-cutting symptom measures exist, and that ICD codes are what appear on claims.
How to study it
One card per disorder: duration, defining feature, nearest neighbor and its distinguishing detail. Do not memorize criterion lists verbatim. The exam tests whether you would diagnose correctly, not whether you can recite.
Practice this. The flashcards and practice tests on this site are sorted by content area, so you can drill this one until it holds.
Duration, feature, neighbor. That is most of the diagnostic content on both exams.