Sanity

'Sanity is a key element in Yandere Simulator''. It determines how much of Yandere-chan's true nature is revealed.'''

When Yandere-chan performs an unethical action, her sanity will decrease. Achieving 0% sanity requires such actions to be performed multiple times.

When Yandere-chan is visibly insane, her head and arms twitch, she hunches over threateningly, her eyes widen, her pupils disappear, and the upper portion of her face darkens. The game's background music will change, becoming slower, lower pitched, and more menacing when compared to the standard background music. Sanity will determine the speed and efficiency with which Yandere-chan performs a murder.

Decreasing Sanity
The ways to decrease sanity are:
 * Drowning someone (-20%)
 * Homicide (-20%)
 * Tranquilizing someone (-20%)
 * Pushing someone off a roof (-20%)
 * Dismemberment (-20%)

In the future, immoral actions such as lying, stealing, trespassing, and taking panty shots may lower sanity as well.

Cardiograph Monitor and Sanity
The cardiograph monitor displays current heart rate, which reflects sanity. It is located at the bottom-right of the HUD. When the player has high sanity, the cardiograph monitor will be light pink, with spikes appearing approximately once per second. If the player is fully insane, the cardiograph monitor will turn bright red and will fluctuate rapidly, indicating an accelerated heart rate.

The cardiograph also displays several intermediate heart rates depending on the player's sanity. As sanity decreases, frequency increases and the cardiograph becomes more red.

80% Sanity
Yandere-chan becomes 80% sane after kidnapping, killing, or dismembering one NPC. Her heart rate becomes a bit faster and her head starts twitching slightly. Her eyes and forehead become very slightly shaded.

60% Sanity
Yandere-chan becomes 60% sane after killing or dismembering two NPCs. Her elbows become slightly bent and the shadow over her face becomes darker. Her pupils fade significantly.

40% Sanity
Yandere-chan becomes 40% sane after killing or dismembering three NPCs. Her face becomes substantially darker. Her pupils become difficult to discern from her irises. The background music becomes distorted.

20% Sanity
Yandere-chan becomes 20% sane after killing or dismembering four NPCs. The cardiograph monitor shows her heart rate in red and a faint vignette appears at the screen's corners. Yandere-chan's back becomes hunched. The shadow over her eyes becomes even darker and her pupils are nearly imperceptible. Staccato piano notes can be heard in addition to the distorted music. The background music heard at 20% sanity can be heard here.

0% Sanity
Yandere-chan loses all of her sanity (0% sane) after killing five NPCs. Her heart rate becomes extremely rapid, her pupils disappear completely, and her face becomes heavily shaded. The game screen is bordered with an obtrusive gray vignette and will noticeably shake.

Reactions of NPCs
If Senpai or a teacher sees Yandere-chan while she is visibly insane, a Game Over will occur (Senpai giving the "Heartbroken" animation and teachers giving the "Expelled" animation).

Meanwhile, if a student sees Yandere-chan in this state, it will instead lower her reputation by ten points if School Atmosphere is high, fifteen points if School Atmosphere is medium, or twenty points if School Atmosphere is low. Apologizing to those who saw the lack of sanity will get 50% of the reputation points back, or 75% if the player wears the Kawaii Moe Shimapan Panties. If a friend or a seduced student sees Yandere-chan, her reputation will be affected by eight points instead. If the player is in the Occult Club, it will take longer for students to notice the insane player.

Low sanity is also incriminating evidence for the police—if the police come to school while the player is visibly insane, they will apprehend Yandere-chan and interrogate her off-screen.

Yokai Story

 * Main Article: Yokai Story

There are five manga volumes scattered around school named Yokai Story. The player can only read one volume each night. Reading these manga volumes will increase Yandere-chan's numbness level, a skill that changes how long it takes to become fully insane. Level 0 (Stoic): It takes five murders to become fully insane.

Level 1 (Somber): It takes six murders to become fully insane.

Level 2 (Detached): It takes seven murders to become fully insane.

Level 3 (Unemotional): It takes eight murders to become fully insane.

Level 4 (Desensitized): It takes nine murders to become fully insane.

Level 5 (Dead Inside): It takes ten murders to become fully insane.

Occult Club

 * Main Article: Occult Club

If the player joins the Occult Club, then the player's sanity will decrease at 50% of the normal rate (i.e. it will take ten kills to become fully insane rather than the usual five). If the player leaves or gets kicked out of this club, then these benefits will no longer be active. If these benefits are combined with Yokai Story, it will take twenty kills to become fully insane.

Tiny Thong Panties

 * Main Article: Panties

If Yandere-chan wears the tiny thong panties, then her sanity will decrease at 50% of the normal rate (i.e. it will take ten kills to become fully insane rather than the usual five). If the player wears tiny thong panties, is a member of the Occult Club, and has a numbness level of 5, it will take thirty kills to become fully insane.

Restoring Sanity
In order to restore sanity to normal, the player can:
 * Laugh hysterically. To do this, tap the Control (PC) or RB (controller) button repeatedly. A Game Over occurs if a teacher or Senpai sees Yandere-chan performing this action. If others hear this sound, it will lower reputation as of the September 1st, 2015 Build. As of the April 15th, 2016 Build, giggling or laughing will cause students to investigate the source of the sound, leaving the target isolated.
 * View pictures of Senpai. To do this, first take pictures of Senpai using Yandere-chan's phone. Next, press Enter (PC) or Start (controller) button and navigate to the photo gallery. Then, select the photo(s) Yandere-chan has taken and "use" it by pressing R (PC). 1980s Mode will not feature the use of the phone.
 * Stand in Senpai's pink aura, though getting noticed will eventually result in a Game Over. If the player is in the Occult Club, then Yandere-chan can stand near Senpai longer without being noticed.
 * Pass the time with the phone. 1980s Mode will not feature the use of the phone.
 * In the future, the player may be able to paint a picture of Senpai to regain sanity when in the Art Club.
 * In the future, the act of being dragged to the Counselor's Office will restore sanity to normal.

Homicide
YandereDev has stated that sanity will have harsher consequences in the future and must be considered in the player's strategies. Killing animations are determined by Yandere-chan's current level of sanity. YandereDev would like them to be as brutal as the killing sequences from Manhunt 1

Stealth: Kills will be efficient, quick, and silent. They will take two seconds.

High: The victim will see the player coming and they will make some noise when they are killed. Bloody, but an efficient kill.

Medium: Yandere-chan's attack is sloppy, as the first strike does not kill completely. It is more noisy and bloody than the previous animation. They will take four seconds.

Low sanity: Yandere-chan brutally and sadistically attacks the victim with many unnecessary strikes, essentially torturing them before landing the killing blow. The victim screams with horror and pain, and there will be blood everywhere. They will take six seconds.

Crawling
Crawling may become less subtle depending on the protagonist's current level of sanity.

High: Looking for dropped contact lens (not suspicious)

Medium: Crawling (suspicious)

No sanity: Dangerous Animal Pose (very suspicious)

As of the August 15th, 2016 Build, the player can test sanity-dependent animations by praying to Mr. Jazzy Feet in the Light Music Club. The player is able to toggle sanity-dependent animations, summon a victim, summon weapons, decrease sanity, or restore sanity while simultaneously cleaning the player's uniform and removing any fingerprints on the weapon. This was added as a debug feature.



Student Sanity
As of the October 17th, 2015 Build, students will also have sanity, which is normally at 100%. However, the main character is able to decrease their sanity when she tortures them in her basement. They will also twitch and have small pupils when their sanity is low. If their sanity is at 0%, then the player can bring them to school and give them a weapon to perform a murder-suicide with the current rival of the week.

Senpai Sanity
Senpai has a hidden sanity variable that will influence some of the game's endings and possibly influence some of his everyday actions. If Hanako Yamada is killed, the Senpai sanity variable would take a big hit. The effects of Senpai's sanity are dependent on budget and volunteers. Yandere-chan is okay with mentally traumatizing Senpai in order to eliminate a rival.

Yanderedev has hinted that if Senpai has witnessed the deaths of all of the rivals/if a significant amount of them die, his sanity will significantly decrease. If Senpai is completely pushed over the edge of insanity, and then finds out that Yandere-chan was the one responsible for the deaths, it is hinted that he may try to harm, or even kill, Yandere-chan.

Depending on Yandere-chan's actions, Senpai might develop PTSD, a personality complex, a nervous disorder, or social anxieties.

Trivia

 * If the player tries to frame a student while having little to no sanity, the police will arrest them both.
 * As of October 2015, Yandere-chan's insane laugh is over eighteen months old, making it one of the oldest assets in the game.
 * YandereDev has stated that a more accurate measurement would be composure rather than insanity, as Yandere-chan is already insane. However, she hides it until murderous deeds cause her true nature to show.
 * In the animation of third degree laughter, the player can see the animation of Yandere-chan's pupils dilating to return back to usual.
 * YandereDev has revealed that he will nerf laughing to restore sanity "once other methods are implemented."
 * In the very old pre-debug builds, instead of a cardiograph, there was a grey meter of a human. After every yandere action, the meter became more red, showing how much sanity has been lost. There was also a face cam of Yandere-chan's eyes. After every Yandere Action, her eyes became more dilated and her smile became bigger. These two HUD functions were later removed.
 * The old Sanity meter was called the Yandere Meter, as seen in a YandereDev video, Yandere Meter Gameplay.
 * YandereDev may implement hallucinations if Yandere-chan's sanity is low. Outdated HUD - 2.png
 * The original Sanity Meter was located on the bottom right corner, slightly skewed.
 * There were two previous animations for the insane laugh that have since been removed.
 * Yandere-chan's original bobcat hairstyle will change depending on her level of sanity. When the player has high sanity, the bangs will be clear from her face and her tufts will bend low. When the player has medium sanity, the tufts will become high and hair will fall over her right eye. When the player has no sanity, the tufts will rise higher and her right eye will be completely covered by bangs.
 * YandereDev is considering the idea that, as Yandere-chan loses sanity, all students will start to look faceless and generic. When Yandere-chan hits 0% sanity, all students will look identical.