Historical evidence for berserkers is mixed. They appear frequently in Icelandic sagas, but these stories were often written centuries after the events they depict, blending fact with fiction.

However, some concrete references do exist. For example:

• The Byzantine Emperor Constantine VII wrote about Norse warriors in his Varangian Guard who exhibited uncontrollable rage in battle.

• The Laws of Norway under King Erik Hakonsson (c. 1015) outlawed berserker behavior, suggesting that such warriors were a real and problematic phenomenon in Norse society.

This legal action points to the idea that berserkers were not just legends but a recognizable group whose behavior sometimes posed threats to social order.

What Caused the Berserker Rage?

Several theories attempt to explain the berserkers’ famed fury:

1. Psychoactive Substances

Some historians argue berserkers may have consumed hallucinogenic mushrooms, particularly Amanita muscaria, to induce altered mental states. The physical effects—agitation, insensitivity to pain, and hallucinations—could mimic the berserk rage. However, modern research casts doubt on this theory; Amanita muscaria is unpredictable and can cause paralysis more often than rage.

2. Mental Illness or Epilepsy

Others propose that berserkers may have suffered from psychological disorders such as hysteria, schizophrenia, or epilepsy, which might explain their unpredictable behavior, trance-like states, and strength outbursts.

3. Battle Frenzy and Adrenaline

A more grounded theory is that berserkers were highly trained warriors capable of entering an adrenaline-fueled trance in battle—akin to the "fight or flight" response on overdrive. This might explain their pain resistance and fearlessness. Comparable states have been recorded among soldiers in more modern wars. shutdown123