A 47-year-old male presents to the psychiatric clinic reporting 3 weeks of depressed mood, anhedonia, insomnia, poor concentration, and passive suicidal ideation. He discloses heavy daily alcohol use (12-15 standard drinks per day) for the past 2 years, with his last drink 5 days ago. He has no prior psychiatric history before the onset of heavy drinking. Review of prior records confirms no depressive episodes prior to the alcohol use escalation. His BAL is 0.00 and he shows no signs of withdrawal. The most appropriate initial diagnostic consideration is: