It seems there may be some confusion in the terminology used. The term "maniac" is not typically used in modern medical or psychological contexts. I believe you might be referring to "mania," which is a symptom associated with bipolar disorder.
To address your question, people experiencing mania (a state of elevated mood, energy, and heightened activity) may not necessarily experience hallucinations. Hallucinations are sensory perceptions that occur in the absence of external stimuli. They can affect different sensory modalities, such as taste (gustatory hallucinations), hearing (auditory hallucinations), and sight (visual hallucinations).
While hallucinations are more commonly associated with certain psychotic disorders like schizophrenia, they can also occur in other conditions, including bipolar disorder, particularly during severe manic or depressive episodes.
So, in the context of a person experiencing a manic episode, it is possible for them to have hallucinations, but it is not a defining feature of mania. It is essential to consult a qualified mental health professional for an accurate diagnosis and appropriate treatment if someone is experiencing symptoms of mania or any other mental health concerns. Treatment and support can help manage these conditions effectively.