Specific phobia, or simple phobia, is an intense and persistent fear caused by the presence or anticipation of a specific object or situation. It causes an immediate anxiety response and often leads to avoidance. Phobias are classified into subtypes including situational, animal, blood-injury, and natural environment. They typically onset in childhood or adolescence. Signs include crying, clinging, avoidance, or panic symptoms. Treatment involves exposure therapy, desensitization, modeling, and in some cases medication to help individuals gradually face their fears.