Diagnosis & Assessment

Diagnosis & Assessment shares the top weighting on the ANCC exam at approximately 25%. This domain tests your ability to apply DSM-5-TR criteria accurately, distinguish between conditions with overlapping presentations, and select appropriate assessment instruments for screening and monitoring.

The exam emphasizes differential diagnosis — the ability to tell apart conditions that look similar. Common pairings include bipolar II vs. borderline personality disorder, ADHD vs. generalized anxiety, delirium vs. dementia, PTSD vs. acute stress disorder, and MDD with psychotic features vs. schizoaffective disorder. You need to know the specific criteria that differentiate each.

Expect questions on validated screening tools (PHQ-9, GAD-7, AUDIT-C, C-SSRS, MDQ), mental status examination components and findings, and medical workups that rule out organic causes of psychiatric symptoms (thyroid panels, B12, RPR, UA toxicology). The exam tests both what to assess and how to interpret results.

• ✕Confusing duration criteria — hypomania requires at least 4 consecutive days (not 7, which is mania), PTSD requires symptoms lasting more than 1 month (vs. ASD which is 3 days to 1 month), and persistent depressive disorder requires at least 2 years of depressed mood.
• ✕Missing the ego-syntonic vs. ego-dystonic distinction. OCD thoughts are ego-dystonic (unwanted and distressing), while OCPD traits are ego-syntonic (the person sees them as reasonable). Hoarding disorder is also ego-syntonic, which differentiates it from OCD with hoarding obsessions.
• ✕Applying adult diagnostic criteria to children. Irritability can meet the mood criterion for MDD in children. DMDD was created specifically to prevent overdiagnosis of pediatric bipolar disorder. Separation anxiety disorder has a different duration threshold for children vs. adults.
• ✕Not accounting for substance use in differential diagnosis. Many psychiatric symptoms resolve after sustained abstinence. The exam tests whether you can distinguish substance-induced disorders from primary psychiatric conditions — the key is timeline relative to substance use.
• ✕Over-relying on screening tool scores as diagnoses. A PHQ-9 score of 15 suggests moderately severe depression but is not a diagnosis — it guides further clinical assessment. The exam tests your understanding that screening tools have sensitivity and specificity limitations.