Differential Diagnosis

• Single Most Likely Diagnosis
  • Cannabis Use Disorder: The patient's daily use of marijuana, self-reported dependence, tolerance, and withdrawal symptoms when trying to quit strongly suggest this diagnosis. The fact that he obtained a medical card with his mother's help and admits to using it daily supports the notion of cannabis use disorder.
• Other Likely Diagnoses
  • Alcohol Use Disorder: Although the patient recently started drinking and the amount is relatively moderate (2-3 drinks), the context of using alcohol in addition to marijuana for self-medication and the family history of substance use (brother providing alcohol) make this a likely consideration.
  • Insomnia Disorder: The patient reports severe insomnia with only 3-5 hours of sleep nightly, which significantly impacts his daily functioning and has led to episodes of prolonged sleep deprivation.
  • Migraine Disorder: Chronic migraines since age 15 are a significant part of the patient's medical history, potentially exacerbated by sleep disturbances and substance use.
  • Post-Traumatic Stress Disorder (PTSD): Given the history of childhood bullying and physical punishment from his father, along with a strained relationship with his father, PTSD should be considered, especially as it can contribute to substance use and sleep disturbances.
• Do Not Miss Diagnoses
  • Psychotic Disorder: The patient's history of visual hallucinations, especially during episodes of severe sleep deprivation, necessitates consideration of a psychotic disorder. The content of the hallucinations ("evil version of myself") could suggest a more severe psychiatric condition.
  • Bipolar Disorder: The episodes of prolonged sleep deprivation, which can be a feature of manic or hypomanic episodes, combined with the patient's substance use and hallucinations, make bipolar disorder a critical diagnosis not to miss.
  • Sleep Disorder (e.g., Narcolepsy): Although less common, the patient's severe sleep disturbances and hallucinations could also suggest a primary sleep disorder, which would require specific diagnostic testing.
• Rare Diagnoses
  • Schizotypal Personality Disorder: The patient's history of visual hallucinations and his social isolation (staying in his room alone for periods) might suggest schizotypal personality traits, but this would be less likely given the context of sleep deprivation and substance use.
  • Kleine-Levin Syndrome: This rare condition involves recurring periods of excessive daytime sleepiness and is often accompanied by automatic behavior, confusion, and hallucinations. However, the patient's symptoms do not fully align with this diagnosis, making it less likely.