Not in the anime, however if you decide to read the manga and make it past where the anime ended, be aware that there is a dog’s corpse during the “forgotten children arc”
Several ghosts have committed suicide. Most notably: In "The Doll House", Mai has a dream about someone drowning herself in a lake, but the suicide, itself, is not depicted. A ghost recounts her failed suicide attempts in "Ghost Story in the Park!?" until she gives up, just to accidentally fall and die. This is played for laughs. There is also a decent amount of suicide in "The Cursed House" committed by possessed people.
Yes! During “A ghost in the park!?!” The female ghost attempts multiple times to take her own life.
Im also not sure if it happens on screen but be weary during the “forbidden past time” episodes, as they feature the ghost of a teenager who had committed suicide
There are children ghosts in "The Doll House" arc, implying that children have died. There are no on-screen children deaths, but there is a point during "The Cursed House" where two possessed children threaten to commit suicide. They do not.
Only verbally. During "Ghost Story in the Park!?" there are several kissing scenes between various people, and a possessed Masako flirts with Naru. The arc ends with Ayako dragging John away, telling him not to worry because she will "be gentle". Also, during this arc, John says something that makes people suspect that he is accusing Masako of being a sex worker, but this suspicion is cleared up very quickly. Other than that, there is some hugging between Naru and Mai.
There is a ghost during "Silent Christmas" who was a nonverbal child who seems written to be a person with autism. He is not malicious, but he believes a man is his father and becomes attached to him. After a while the man gets angry and says he's not his father. This is as close as it gets to abuse.
During "The Doll House" a flame appears in one room, but nobody gets hurt. At the end of "The Bloodstained Labyrinth", a building is vacated and burned down to get rid of a ghost.
Knives are implied to be used in the dreams Mai have in "The Bloodstained Labyrinth", but no cutting is shown. In "The Cursed House", children have multiple mild lacerations show up on their back after an exorcism. The act of cutting isn't show, but they are cut up.
There are some scenes of restraint where mai has to be (gently) held back and I believe there are some more violent restraint scenes during the bloodstained labyrinth if my memory is correct.
Mai can scream and panic a few times. Masako can become scared and despondent at times in cases where ghosts are in agony. During "The Cursed House", a ghost is interviewed and seen panicking.
Casualties happen in the final two arcs only, specifically in Bloodstained Mansion and The Cursed House. Any other casualties are actions which happened in the past.
Offscreen, a student jumps off a building to his death during the "Forbidden Pastime" arc. During "The Cursed House" arc, some possessed people jump off a cliff to their deaths.
An ambulance picks up someone during "Evil Spirits All Over!?" and a school infirmary is a common location in "The After-School Hexer", and someone is sent to the hospital near the end of the arc. The audience only sees him in his room in bed with no medical tools to be seen, though someone does bring flowers for him. The final scene of the show at the end of "The Cursed House" shows the group in a hospital visiting someone in a bed. No medical equipment shown.
There is a scene where a character finishes bathing herself, and you see her exiting the bathroom in what appears to be a bathrobe or pajamas. No private parts are shown.
During "The Doll House", a flashback indicates that a child was led away from home by an adult stranger and never returns. In "The Bloodstained Labyrinth", people seemingly disappear, and it is revealed that something is abducting and killing them.
In the "After-School Hexer" arc, a cursed desk apparently causes its user to get their arms caught in a moving subway and lose them. You do not see any of these victims, nor do you see the act happen.
In "The Doll House", a flashback reveals a mother killed herself. A parent probably dies in "The Cursed House", but the familial relations are hard to keep track of.
In "The Doll House", a girl is hurt by a possessed doll whenever she doesn't do what the ghosts tell her. Two children in "The Cursed House" end up bleeding from cuts on their back that formed after an exorcism.