Noctiphobia, also known as nyctophobia, is a type of anxiety disorder characterized by an irrational and persistent fear of the dark. Symptoms can include sweating, trembling, palpitations, and panic attacks, and can lead to avoidance behaviors such as staying indoors at night. There are several synonyms for noctiphobia, including lygophobia, achluophobia, and scotophobia. While these terms may be less well-known than nyctophobia, they all refer to the same condition and can be helpful in describing the fear of darkness to others. Treatment for noctiphobia may include cognitive-behavioral therapy, exposure therapy, and medication.