Differential Diagnosis for Adolescent Patient with Delusions and Visual Disturbance

Single Most Likely Diagnosis

• Benzodiazepine Withdrawal Psychosis: The patient's history of using street-bought "benzos" and then tapering off, followed by delusions and possible visual disturbances, strongly suggests benzodiazepine withdrawal psychosis. This condition can occur when the body is suddenly deprived of the drug after a period of dependence, leading to severe psychological symptoms.

Other Likely Diagnoses

• Substance-Induced Psychotic Disorder: Given the patient's recent history of substance use, it's possible that the delusions and visual disturbances are directly related to the effects of the substance or its withdrawal.
• Sleep Deprivation Psychosis: The patient has been experiencing sleep disturbances, which can lead to psychotic episodes, including delusions and hallucinations, in vulnerable individuals.
• Underlying Psychotic Disorder: The patient's symptoms could be the manifestation of an underlying psychotic disorder, such as schizophrenia, which has been triggered or exacerbated by substance use and withdrawal.

Do Not Miss Diagnoses

• Neuroleptic Malignant Syndrome (NMS): Although less likely, NMS is a life-threatening condition that can be triggered by certain medications or substances. It presents with fever, muscle rigidity, and altered mental status, which could initially be mistaken for psychosis.
• Serotonin Syndrome: This is another potentially life-threatening condition caused by excessive levels of serotonin, often due to the use of certain medications or substances. Symptoms can include altered mental status, agitation, and hallucinations.
• Intracranial Infection or Hemorrhage: Delusions and visual disturbances could be symptoms of an underlying and serious neurological condition such as a brain infection or hemorrhage, which would require immediate medical attention.

Rare Diagnoses

• Temporal Lobe Seizures: These seizures can present with psychotic symptoms, including delusions and visual hallucinations, and are a rare but important consideration in the differential diagnosis.
• Vitamin Deficiency-Related Psychosis: Certain vitamin deficiencies, such as those involving B12 or niacin, can lead to psychotic symptoms. This would be more likely in the context of poor nutrition or specific medical conditions affecting absorption.