Arithmomania is a mental disorder that may be seen as an expression of obsessive–compulsive disorder (OCD). Individuals suffering from this disorder have a strong need to count their actions or objects in their surroundings. 
Sufferers may for instance feel compelled to count the steps while ascending or descending a flight of stairs or to count the number of letters in words. They often feel it is necessary to perform an action a certain number of times to prevent alleged calamities. Other examples include counting tiles on the floor or ceiling, the number of lines on the highway, or simply the number of times one breathes or blinks, or touching things a certain number of times such as a door knob or a table.
Arithmomania sometimes develops into a complex system in which the sufferer assigns values or numbers to people, objects and events in order to deduce their coherence. Sometimes numbers are linked to the past events and the person remember the events again and again by particular numerical values. One performs their actions a particular number of times, and this number is linked to their particular satisfied event.[clarification needed]
Counting may be done aloud or in thought or in sequences of daily emails on ascending integer themes.
Arithmomania in popular culture
- Count von Count, a Sesame Street Muppet whose main personality trait is the fact that he can't resist counting things; in historic folklore, vampires were often combatted by placing great quantities of items (sand grains, seeds, etc.) near them in order to keep them occupied.
- Count in Fives, a song by the English garage rock band The Horrors is about a man addicted to counting in fives, with a dislike of other numbers.
- In The Elder Scrolls IV: Shivering Isles, the expansion to the video game The Elder Scrolls IV: Oblivion, there is a Bosmer ghost in Vitharn named Althel who counts in a sequence of specific numbers every time she talks. There is also an Imperial woman named Jastira Nanus in the town of Split, who, like the other residents, has two versions of herself. Both versions are obsessed with counting; the main difference is the Manic version counts every time she talks, while the Demented version prefers counting corpses.
- In The X-Files episode "Bad Blood", Fox Mulder mentions that if vampires find some seeds scattered, they can't resist picking them up and counting them. He later spills a bag of seeds to aid in his escape, the pursuer unwillingly stopping to pick them up.
- In Supernatural Season 6 Episode 9 "Clap Your Hands If You Believe", Sam and Dean Winchester are investigating a series of unusual disappearances in Elwood, Indiana. They interview a woman who claims that fairies are behind the disappearances. She informs Sam and Dean that any fairy, no matter how powerful, must stoop to count each grain of sugar or salt that has been spilled in front of them. The Leprechaun then tries to make a deal with Sam to give him his soul back, but Sam refuses. They fight until Sam spills salt in front of him, and he is forced to start counting the grains. Sam then reads a ritual and the fairies are banished back to their realm.
- In The Subtle Knife, the second book of Philip Pullman's His Dark Materials, Will Parry's mother displays arithmomania along with paranoia. Seeing similar behaviour in the world of Cittàgazze Will and Lyra Silvertongue hypothesize that arithmomania is an attempt to defend against Spectres by generating Dust.
- The character Tamotsu Fukuda in the anime ID: Invaded is driven mad by his arithmomania, going so far as to drill a hole in his head to try and block his thoughts. Prior to having the hole, he was able to remember every sequence of numbers he came across, including exact dates and times. In one scene he is also shown counting grains of sand in a desert. He states that his favorite number is three, and that he has a strong dislike for people that like the number seven.