A 43-year-old married man is admitted to an inpatient hospital for acute hepatitis. The PMHNP is consulted for a psychiatric evaluation after he admits to a long history of alcohol use beginning in college. He has gradually increased his nightly alcohol intake from a single 6-pack of beer to two 12-packs of beer, and his drinking has caused him to oversleep and miss work on occasion. He has had his wife phone in sick for him from time to time. He has tried to cut down on his drinking with little success. He admits he does have tremors and becomes anxious when he doesn't drink. Which diagnosis appears to be appropriate for this patient, based on this information?