Which of the following is NOT categorized as a psychiatric condition?

Substance abuse is generally classified under substance use disorders rather than psychiatric conditions themselves. While it does impact mental health and can lead to psychiatric symptoms, it fundamentally revolves around the misuse of substances like drugs or alcohol. This distinction is important because, while the other options—Alzheimer's disease, depression, and schizophrenia—are primarily recognized as psychiatric disorders and are included in diagnostic manuals such as the DSM (Diagnostic and Statistical Manual of Mental Disorders), substance abuse is more focused on the behavioral and physical consequences of substance ingestion.

Alzheimer's disease, though it presents with cognitive decline, is categorized as a type of dementia and has both neurological and psychological elements, placing it still within the broad realm of psychiatric disorders. Similarly, depression and schizophrenia are considered classic psychiatric diagnoses, each with specific symptoms and treatment modalities. Substance abuse, however, emphasizes the behavioral aspects of substance consumption and the complications arising from it, thereby making it distinct from the more strictly defined psychiatric conditions.