Which of the following symptoms is a hallmark of schizophrenia?

Hallucinations are indeed a hallmark symptom of schizophrenia. These experiences may involve seeing, hearing, or feeling things that are not present in reality, and they significantly distinguish schizophrenia from other mental health disorders. Hallucinations can greatly impair an individual’s ability to function and interact with their environment, as they often lead to a distorted perception of reality. This symptom is part of the characteristic psychotic features seen in schizophrenia, which also includes delusions and disorganized thinking.

In contrast, while depression, anxiety attacks, and obsessive thoughts may occur in various mental health conditions, they are not central to the diagnosis of schizophrenia. Depression could be present in mood disorders like major depressive disorder or bipolar disorder, while anxiety attacks are commonly seen in anxiety disorders. Obsessive thoughts typically relate to obsessive-compulsive disorder. Each of these symptoms can manifest in different clinical contexts, but they do not define schizophrenia specifically like hallucinations do.