πανικός

Pan was a god of shepherds, forests, and wild places—half man, half goat, patron of Arcadia in the central Peloponnese. He was not one of the twelve Olympians. He was older, stranger, more animal. The Greeks believed Pan took naps in the midday heat, and disturbing his sleep provoked a shriek that caused irrational, stampeding terror in anyone who heard it. They called this panikon deima—'panic fear,' the fear that comes from Pan.

The word had military currency. Herodotus, writing around 440 BCE, reported that Pan helped the Athenians at the Battle of Marathon in 490 BCE. The night before the battle, the runner Pheidippides encountered Pan in the mountains and the god asked why the Athenians did not worship him. After the Athenian victory, they dedicated a shrine to Pan beneath the Acropolis. The military panic that struck the Persians was attributed to the god's intervention.

Greek panikos entered Latin as panicus and arrived in English through French panique in the 1600s. The first recorded English use of panic as a noun—not an adjective—was in 1708, in a philosophical essay by the Earl of Shaftesbury. He used it to describe irrational crowd behavior. By the 1800s, financial crises were called panics: the Panic of 1819, the Panic of 1837, the Panic of 1893. A goat-god's scream had become an economic term.

Modern psychology recognizes panic attacks and panic disorder as clinical conditions distinct from ordinary anxiety. The DSM-III formalized the diagnosis in 1980. The word has traveled from a forest god's nap to a psychiatrist's office. But the core meaning has not changed: panic is fear that arrives without rational cause and overwhelms the capacity to think.