paranoia is a mental state that involves excessive fear or mistrust of others, even when there is no evidence or very little evidence to support it. paranoia can affect how a person thinks, feels and behaves. It can be caused by various factors, such as stress, trauma, drug use, genetics or brain chemistry. This can also be a symptom of a mental disorder, such as schizophrenia or paranoid personality disorder. paranoia can interfere with a person’s daily functioning and relationships, and may require treatment with psychotherapy and medication.
