Hallucination is a perception that occurs without an external stimulus, meaning a person experiences something that isn't actually there. This can involve seeing, hearing, feeling, or even tasting things that do not exist in reality. Hallucinations can be caused by various factors, including mental health conditions like schizophrenia, substance use, or extreme fatigue. These experiences can vary in intensity and duration, and they may be distressing or confusing for the individual. While some hallucinations are benign, others can lead to significant challenges in daily life. Understanding the underlying causes is essential for effective treatment and support.