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Humans exposed to kryptonite often develop a kryptonite-inspired psychosis, where they lose contact with reality and become obsessed with following their natural instincts.

The psychosis afflicts not only kryptonite-infected metahumans, but also some humans who become temporarily metahuman as a result of kryptonite exposure.

The transfer of Kryptonian powers to humans may also trigger kryptonite psychosis. Kryptonian powers have been transferred from Clark Kent to two separate humans: Eric Summers and Lana Lang. Similar powers were also given to Jeremiah Holdsclaw through the presumably Kryptonian Starblade. In all three cases, the humans exhibited many of the symptoms of kryptonite psychosis. It is unknown whether this is a form of common psychosis or if actually possessing Kryptonian powers is the cause. However it is important to point out that Lois Lane absorbed Kryptonian powers from Clark and suffered no such ill effects (although it should be noted that Kryptonite was not involved in the transfer) indicating that one's emotional state and stability play a vital role in exacerbating or even negating the possibility of contracting this induced psychosis (given that Lois was of a more benevolent and stable disposition that Eric, Lana or Jeremiah).


Kryptonite psychosis seems to enhance the instinctual desires of the infected individuals. As Clark said to Greg Arkin in Metamorphosis, when you are infected with kryptonite, "you're a slave to your instincts."

When exhibiting the symptoms of kryptonite psychosis, individuals often lose the ability to evaluate the moral dimensions of their decisions; this frequently results in homicidal behavior. Coach Walt Arnold was willing to do anything to win, including using his powers to intimidate or even kill others. Other freaks of the week exhibited similar homicidal behavior; many of these metahumans ended up at Belle Reve.

Kryptonite psychosis can result in non-homicidal behavior if the infected subject does not have homicidal tendencies. For example, Chloe Sullivan abused her temporary truth-coercion powers to invade the privacy of others, including her best friends. That said, she never attempted to kill or hurt anyone with her powers.


Some humans have proven to be immune to the usual psychosis that comes from kryptonite infection. All of these people had good intentions, hinting that kryptonite psychosis may only enhance malevolent intentions or instincts which are already strong.

  • Cyrus Krupp avoided the usual symptoms of psychosis from his Healing powers, although he did eventually suffer a complete mental breakdown. (Visitor)
  • Chloe Sullivan has not developed kryptonite psychosis despite having the meteor-inspired power of empathic healing.
  • Cassandra Carver never developed psychosis despite developing precognition. (Hourglass)
  • Jordan Cross avoided psychosis despite gaining his precognition powers from the meteor shower of 1989. (Hereafter)
  • Tobias Rice could "see" other metahumans despite being blind; he never developed psychosis. (Freak)
  • Kevin Grady could create amnesia, but never developed psychosis. (Blank)
  • Kyle Tippet could influence people with his handshake, but never developed psychosis. Bob Rickman, on the other hand, developed the same power from the same kryptonite exposure and became drunk with power. (Hug)
  • Maddie Van Horn could control glass from kryptonite infection and never developed psychosis, although she was close to killing her father. However, her father Tyler McKnight was a homicidal maniac, suggesting that kryptonite psychosis can't be inherited or that his instability was pre-existing and developing powers only gave him the incentive or means to act on it. (Fragile)
  • Abigail Fine developed the ability to give people hallucinations when she kissed them, but never developed a psychosis. (Facade)


The only known cure for kryptonite psychosis is to cure the underlying kryptonite-inspired powers. Dr. Curtis Knox developed such a cure that removed both the kryptonite-inspired powers and the kryptonite psychosis. Sasha Woodman was cured by Dr. Knox, before he killed her to harvest her organs. (Cure)

It is possible that kryptonite psychosis cannot be cured by merely inhibiting powers, rather than completely removing them. Alicia Baker's were inhibited by a lead bracelet after she was freed from Belle Reve, but she still used red kryptonite to force Clark to leave Smallville. This hints that Alicia may have still been a slave to her instincts, despite her powers being inhibited. This is by no means a certain conclusion; she may have simply used bad judgment.

Chloe Sullivan was so afraid of kryptonite psychosis that she asked Dr. Knox to cure her of her abilities, despite the side effect of losing her memories.

Lana Lang, Pete Ross, and Chloe were all cured of kryptonite psychosis after they lost their temporary powers.

Main characters

Several main characters have developed mild psychosis while temporarily metahuman, in a matter similar to the freaks of the week from Season One.

  • Lana Lang, along with her Tri Psi sorority sisters, killed with no conscience when infected by a meteor-rock-mutated form of rabies. (Thirst) Also, after she temporarily leeched off Clark's powers, she became obsessed with using them for revenge against Lex(very similar to when Eric Summers leeched Clark's powers). (Wrath)
  • Chloe Sullivan also went drunk with power when she acquired the power to coerce the truth from others due to kryptonite exposure. (Truth)
  • Pete Ross had jealousy and narcissistic tendencies that were greatly amplified when he chewed kryptonite-infected chewing gum. (Hero)


  • Chloe Sullivan is the only known case of someone who has gained powers twice, but only developed kryptonite psychosis once. The first time she temporarily developed the ability to extract the truth from others, her primary instinct was to find out the truth about Clark. The second time she gained the more permanent healing powers (although they are currently not working). As these powers cannot be used in a destructive way, this could explain why the manifestation of her healing powers has not led to kryptonite psychosis.
  • No one who demonstrates precognition or healing powers is known to have developed kryptonite psychosis. This could be because these powers are more defensive or supplementary in nature, and can't be used to hurt or destroy others, or may inherently provide the infectee with some defense against this side-effect.
  • As a result of the many cases of kryptonite psychosis, many Smallville residents are biased against people with powers. Lana Lang was slightly against meteor freaks for years due to the fact that all the ones that she had met tried to kill her. Jimmy Olsen was biased against them. This caused problems for both, as both of their romantic partners (Clark Kent and Chloe Sullivan) were metahumans afraid to reveal their powers to their loved ones.
  • Kryptonians have never exhibited kryptonite psychosis due to exposure to green kryptonite. However, red kryptonite has similar effects on Kryptonians, removing inhibitions and heightening base instincts.
  • Green kryptonite is the only example of kryptonite causing psychosis in humans; Reverend Joseph Cavanagh went insane after the loss of his daughter and his town's water supply being contaminated by blue kryptonite, but this appeared to be a relatively natural insanity caused by his grief over the loss of his daughter rather than being kryptonite-induced (Harvest).
  • Lana and Eric Summers also developed a mild psychosis when they acquired Clark Kent's powers and abilities through kryptonite/electricity exposure. (Leech, Wrath) Eric terrorized his classmates and was destructively violent. Lana tried to fulfill her vengeance against Lex Luthor by exposing his crimes and attempting to kill him. Interestingly, Lana was completely cured after the powers were transferred back to Clark, but Eric remained unstable (although this could be the result of the psychological abuse he suffered from his father).


Clark: Jake was exposed to the meteor rocks. He didn't ask for them.
Lana: No, just like Greg Arkin didn't ask to become a bug boy and Tina Greer didn't ask to become a bone morpher. Look, the fact is when they got their powers, they went psycho and tried to kill me. Tina even came back for seconds. Chloe's been attacked by more of these people than me. You remember Justin Gaines and Sean Kelvin.
Chloe: Yeah, one tried to psychically impale me with farm implements and the other just wanted my body heat. Thanks for the memories.
Season Three, Extinction

Sasha: Do I know you?
Chloe: Chloe Sullivan. Freshman year, you tried to go queen bee and kill two of my best friends. How did you get past the orderlies?
Sasha: You don't understand. I don't belong in Belle Reve. I'm not a meteor freak anymore. I've been cured. A few weeks ago, I had an operation.
Chloe: Operation? Who was the doctor?
Sasha: Curtis Knox. He changed my life. My family told me about the terrible things I did in the past, but I'm different now.
Chloe: What do you mean your family told you?
Sasha: When they took away my powers, some of my memory went along with it. The last...six years are blank. If I did anything to you or your friends, I'm really sorry.
Season Seven, Cure

Chloe: You don't understand, Clark. Going psycho or turning into a serial killer aren't the only two things I have to worry about. When I healed Lois in that dam, it almost killed me. Who's to say the next time I try and save someone isn't my last?
Season Seven, Cure

Clark: If he ingests any more kryptonite... we both know what happens to people.
Chloe: Present company on stand-by.
Season Seven, Hero
Kryptonite in Smallville
Types Natural: GreenRedBlueGold kryptonite • Processed: BlackSilverGemstoneClear kryptonite
Effects Meteor infectionPsychosisMeteor freaks
Objects BulletCageHandcuffsHeartKeyRingNecklaceVictory ring
Other KryptonMeteor showers (1989, 2005) • Lead (box) • Appearances of Green K (usages)