Differential Diagnosis for a 16-year-old with Erratic Behavior and Extreme Mood Swings

• Single most likely diagnosis:
  • A. Anabolic steroid abuse: This condition is likely given the patient's history of playing sports and the symptoms described, such as irritability, aggression, and feelings of invincibility. Anabolic steroid use is known to cause mood swings, aggression, and a sense of grandiosity, which aligns with the patient's behavior and feelings of being able to fly.
• Other Likely diagnoses:
  • B. Marijuana intoxication: While marijuana can cause altered perceptions and mood changes, the specific combination of irritability, aggression, and feelings of invincibility, especially in the context of sports participation, makes this less likely than anabolic steroid abuse. However, it remains a possibility, especially if the patient is using marijuana regularly.
  • C. Normal teenage development: Mood swings and irritability can be part of normal teenage development, especially during puberty. However, the severity of symptoms described, including feelings of invincibility and aggression towards others, suggests that there may be more than typical adolescent behavior at play.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • D. Viral encephalopathy: Although less likely, viral encephalopathy can cause significant alterations in behavior, including mood swings, irritability, and even psychosis. Given the potential severity of encephalopathy, including the risk of death or long-term neurological damage, it is crucial not to miss this diagnosis, even if it seems unlikely based on the initial presentation.
• Rare diagnoses:
  • Other rare conditions that could potentially cause these symptoms include bipolar disorder, schizophrenia, and substance-induced psychotic disorder. However, these would be less likely given the acute onset and the specific context of sports participation, unless there is a pre-existing condition or other substances are involved.