Final answer:
Anhedonia should be documented as a negative symptom of schizophrenia, representing a loss of pleasure or interest in life activities, distinct from positive symptoms like delusions.
Step-by-step explanation:
A nurse assessing a client who has schizophrenia should document anhedonia as a negative symptom of this disorder. Unlike delusions and neologisms, which are considered positive symptoms indicative of psychosis, anhedonia represents a negative symptom characterized by a loss of pleasure or interest in life activities. Negative symptoms are often associated with a flattened emotional state and the loss of basic drives, which are key aspects in the management of schizophrenia.