Does it impair her ability to function?
According to the Mayo Clinic these are the symptoms of Schizophrenia:
Delusions. These are false beliefs that are not based in reality. For example, you’re being harmed or harassed; certain gestures or comments are directed at you; you have exceptional ability or fame; another person is in love with you; a major catastrophe is about to occur; or your body is not functioning properly. Delusions occur in as many as 4 out of 5 people with schizophrenia.
Hallucinations. These usually involve seeing or hearing things that don’t exist. Yet for the person with schizophrenia, they have the full force and impact of a normal experience. Hallucinations can be in any of the senses, but hearing voices is the most common hallucination.
Disorganized thinking (speech). Disorganized thinking is inferred from disorganized speech. Effective communication can be impaired, and answers to questions may be partially or completely unrelated. Rarely, speech may include putting together meaningless words that can’t be understood, sometimes known as word salad.
Extremely disorganized or abnormal motor behavior. This may show in a number of ways, ranging from childlike silliness to unpredictable agitation. Behavior is not focused on a goal, which makes it hard to perform tasks. Abnormal motor behavior can include resistance to instructions, inappropriate and bizarre posture, a complete lack of response, or useless and excessive movement.
Negative symptoms. This refers to reduced ability or lack of ability to function normally. For example, the person appears to lack emotion, such as not making eye contact, not changing facial expressions, speaking without inflection or monotone, or not adding hand or head movements that normally provide the emotional emphasis in speech. Also, the person may have a reduced ability to plan or carry out activities, such as decreased talking and neglect of personal hygiene, or have a loss of interest in everyday activities, social withdrawal or a lack of ability to experience pleasure.
Since she is hearing things that others don’t seem to hear we assume she is either delusional or experiencing hallucinations or both. Does she appear to have any of the other possible symptoms?