Which of the following best represents medical etiologies that can mimic psychiatric illness and present with altered mental status?

• A. Metabolic disturbances (electrolytes, glucose), thyroid disorders, vitamin deficiencies (B12, folate), hepatic/renal failure, infections (encephalitis), CNS tumors, stroke, autoimmune or infectious processes, and drug effects.
• B. Only metabolic disturbances (electrolyte imbalance) are responsible.
• C. Only thyroid disorders cause altered mental status.
• D. Only CNS tumors cause altered mental status.

Answer: (A)

The key idea is that altered mental status often results from medical problems that can masquerade as psychiatric illness. The brain doesn’t operate in a vacuum; systemic issues can disrupt cognition, mood, and behavior in ways that mimic primary psychiatric disorders. This is why a thorough medical eval is essential whenever someone presents with confusion, agitation, delusions, or mood changes.

All of the following can produce cognitive or behavioral changes and delirium: metabolic disturbances (like electrolyte imbalances and abnormal glucose), thyroid disorders, vitamin deficiencies (notably B12 and folate), hepatic or renal failure, infections affecting the brain (such as encephalitis), central nervous system tumors, stroke, autoimmune or infectious brain processes, and the effects of drugs. Each category can alter brain function through different mechanisms—electrolyte or glucose shifts disrupt neuronal signaling; thyroid hormones modulate metabolism and thought; B12/folate are critical for myelin and neurotransmitter synthesis; liver or kidney failure leads to toxin buildup; infections and inflammatory processes can inflame or damage brain tissue; tumors and strokes cause focal or global functional changes; and drugs can depress, excite, or confuse neural activity.

This breadth makes the first option the best choice because it acknowledges that many medical conditions can present with psychiatric-like symptoms and altered mental status, not just a single cause. The other options are narrower, implying only one category can cause these changes, which isn’t accurate in real clinical practice. In exams and in care, always consider medical mimics and perform an appropriate medical workup to avoid misdiagnosing a treatable medical problem as a primary psychiatric disorder.