Final answer:
Schizophrenia, once known as dementia praecox, is a serious mental disorder characterized by hallucinations, delusions, and difficulty distinguishing reality from imagination.
Step-by-step explanation:
The term that was formerly known as dementia praecox, which does not indicate that a patient has multiple personalities, is schizophrenia. Schizophrenia is a mental illness characterized by symptoms such as hallucinations, delusions, and the inability to differentiate between reality and imagination. It may also entail negative symptoms such as a flattened emotional state and loss of basic drives. Treatment typically involves antipsychotic medications that block dopamine receptors to manage symptoms. Despite treatment, schizophrenia is a lifelong condition, and patients will usually need to remain medicated indefinitely.