What defines negative symptoms in individuals with schizophrenia?

Negative symptoms in individuals with schizophrenia refer to the absence or reduction of normal emotional and behavioral functions. These symptoms contrast with positive symptoms, which include behaviors like hallucinations and delusions.

When looking at behaviors found in normal people, it highlights what individuals with schizophrenia may lack. For instance, a person without schizophrenia typically exhibits a full range of emotional and social engagement. In someone with negative symptoms, these aspects may be diminished. This could manifest as a lack of motivation, reduced emotional expression, social withdrawal, or an inability to experience pleasure.

The other options describe behaviors that are either positive symptoms (such as hallucinations) or characteristics that can be seen in various contexts (like extreme enthusiasm or aggression) but do not align with the concept of negative symptoms, which specifically indicate a deficit or lack. Therefore, option B accurately reflects the essence of negative symptoms by identifying them as the absence of typical, healthy behaviors present in people without the disorder.