A 45-year-old man reports the police are stealing food from his home, a belief that is most likely a symptom of which disorder?

The belief that the police are stealing food from the man's home is indicative of a delusional disorder, which is characterized by the presence of one or more delusions that persist for a month or longer. These delusions are typically false beliefs that are firmly held despite evidence to the contrary and are often plausible but not based in reality. In this case, the man's belief about the police implies a specific and persistent misunderstanding of reality that aligns with the criteria for delusional disorder.

While other disorders like schizophrenia and depression can involve delusions or hallucinations, they often include additional symptoms that are not evident in just the belief presented. For instance, schizophrenia encompasses a wider range of symptoms, including cognitive impairment, disorganized thinking, and other negative symptoms, making it less likely that this singular delusion is the core issue. Delirium is marked by acute confusion and fluctuating consciousness, which doesn’t align with a consistently held firm belief. Hence, the man's report most closely aligns with delusional disorder due to the nature and specificity of the delusion concerning the police.