Reference

Guide | Reference

20 Differential Diagnosis Engine

Purpose. Provide a consistent logic for competing explanations. Reduce premature closure and diagnostic overconfidence.

20.1 Always Consider

Delirium or acute confusional state. [E0/U2]
Substance intoxication or withdrawal. [E0/U2]
Medication or iatrogenic effects. [E0/U2]
Sleep disorders masquerading as psychiatric symptoms. [E0/U2]
Endocrine, neurologic, infectious, or inflammatory mimics when indicated. [E0/U2]

20.2 Time-Course Logic

Acute onset → prioritize medical/substance causes. [E0/U3]
Episodic → consider triggers, cyclicity, or episodic prototypes.
Chronic/stable → consider developmental patterns or entrenched traits.
Progressive decline → evaluate neurocognitive and medical causes. [E0/U2]

20.3 Context Logic

Proportional reactions to clear stressors vs persistent dysregulation.
Safety threats and ongoing adversity can dominate presentation.
Cultural or spiritual frameworks may shape symptom language.

20.4 Developmental Anchoring

Compare to age-expected behavior and milestones.
Consider neurodevelopmental patterns when longstanding.

Red flags

New onset psychosis or mania. [E0/U3]
Sudden cognitive change or fluctuating attention. [E0/U3]
New symptoms after medication changes or substance use. [E0/U3]

Documentation Output. Competing explanations listed explicitly. Confidence level (high/medium/provisional). Rule-outs pursued or deferred.