Differential Diagnosis

The patient's symptoms of paranoia, withdrawal, poor self-care, sleep disturbances, diminished appetite, auditory hallucinations, and delusions of poisoning suggest a psychiatric or neurological disorder. Here's a categorized differential diagnosis:

• Single most likely diagnosis
  • Schizophrenia: The patient's symptoms of auditory hallucinations, delusions, disorganized thinking, and negative symptoms (e.g., withdrawal, poor self-care) are characteristic of schizophrenia. The onset of symptoms at age 22 is also consistent with the typical age of onset for schizophrenia.
• Other Likely diagnoses
  • Schizoaffective disorder: This disorder is characterized by a combination of schizophrenia symptoms (e.g., hallucinations, delusions) and mood disorder symptoms (e.g., depression, mania). The patient's diminished appetite and sleep disturbances could be indicative of a depressive episode.
  • Brief psychotic disorder: This condition is characterized by a sudden onset of psychotic symptoms (e.g., hallucinations, delusions) that last for at least one day but less than one month. The patient's symptoms have been present for two weeks, which is within the time frame for this diagnosis.
  • Major depressive disorder with psychotic features: The patient's symptoms of diminished appetite, sleep disturbances, and poor self-care could be indicative of a depressive episode, and the presence of hallucinations and delusions suggests psychotic features.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Neurosyphilis: Although the patient's CT scan of the brain is normal, neurosyphilis can cause psychiatric symptoms, including hallucinations and delusions. A missed diagnosis of neurosyphilis could lead to serious complications, including dementia and death.
  • Autoimmune encephalitis: This condition is characterized by inflammation of the brain and can cause psychiatric symptoms, including hallucinations and delusions. A missed diagnosis of autoimmune encephalitis could lead to serious complications, including seizures, coma, and death.
  • Thyroid dysfunction: Although the patient's laboratory results are normal, thyroid dysfunction (e.g., hyperthyroidism, hypothyroidism) can cause psychiatric symptoms, including hallucinations and delusions. A missed diagnosis of thyroid dysfunction could lead to serious complications, including cardiac problems and death.
• Rare diagnoses
  • Temporal lobe epilepsy: Although the patient has no history of seizures, temporal lobe epilepsy can cause psychiatric symptoms, including hallucinations and delusions. The patient's normal CT scan of the brain makes this diagnosis less likely, but it is still a possibility.
  • Wilson's disease: This rare genetic disorder can cause psychiatric symptoms, including hallucinations and delusions, as well as neurological symptoms. Although the patient's laboratory results are normal, Wilson's disease is a rare condition that can be missed if not considered.