This review covers six medical conditions—acute intermittent porphyria, anti-NMDA receptor encephalitis, lupus, Lyme disease, neuroendocrine tumors, and syphilis—that can masquerade as psychiatric disorders. These illnesses often show up with psychiatric symptoms like anxiety, psychosis, or mood changes, mixed with physical signs such as rashes, abdominal pain, or heart irregularities. Getting the right diagnosis is essential since many cases improve with medical treatment, though you may still need to provide psychiatric care for lingering symptoms. It’s a reminder to stay curious when symptoms don’t quite fit the usual psychiatric picture.