how come lunacy is derived from the word "lunar"?

Answer 1

It was once believed, and to some degree still is, that the moon had a large effect on the human psyche, the way it does on the ocean tides. It was widely held that the full moon had the effect of heightening madness, and making people more prone to doing insane acts.

Answer 2

A lunatic (colloquially: "loony") is commonly used term for a person who is mentally ill, dangerous, foolish or unpredictable, a condition once called lunacy.

The word is borrowed via French from Latin "lunaticus", which gains its stem from "luna" for moon, which denotes the traditional link made in folklore between madness and the phases of the moon. This probably refers to the symptoms of cyclic mood disorders such as bipolar disorder or cyclothymia, the symptoms of which may also go through phases. As yet there is little evidence for any causal link between phases of the moon and the progression of mood disorder symptoms.

In a 1999 paper, Raison et al. put forward the interesting hypothesis that the phase of the moon may in the past have had an effect on bipolar patients by providing light during nights which would otherwise have been dark, and affecting susceptible patients through the well-known route of sleep deprivation. With the introduction of electric light, this effect would have gone away, as light would be available every night, explaining the negative results of modern studies. They suggest ways in which this hypothesis might be tested.

Mental institutions used to be called "lunatic asylums" or colloquially, "loony bins" (the latter term is still occasionally used both humorously and insensitively).

In Russian, a lunatic refers to a sleepwalker, literally "one who walks under the moon" or "moonwalker".

Answer 3

The full moon is said to drive people insane. This old wives' tale still survives. In Ian Fleming's 007 novel "Dr. No", Donovan "Red" Grant is a manic-depressive (now bipolar affective disorder) whose cycles are determined by the full moon. He must kill then. He begins by seeking sleeping bums. In the finale, he tries to kill James Bond, Agent 007. Werewolves are said to change into beasts when the Moon becomes full. This idea of "moon madness" was well-accepted at one time, bit it is considered nonsense by now.

Answer 4

They used to believe, the moon drove people crazy. For example, the Werewolf legend.

Answer 5

Because long time ago it was believed that there was a kind of insanity triggered by the moon's cycle

Answer 6

the moon is related to romance & love-making & love is a kind of madness

Answer 7

the old myth that the full moon makes people crazy

Answer 8

It may soon evolve to "Yahoonacy".