Throughout the entire movie the main character experiences panic attacks.

One character has recurring panic attacks throughout the film

Main character Klaus is often shown having flashbacks or nightmares because of trauma he's suffered due to his powers and his father. These usually send him into having some sort of anxiety or panic attack until he uses drugs to stop them.

When Peter is with his friends under the bleachers, he has an anxiety attack

When he's stressed, Arthur (the Joker) is laugthing wiyhout any control. It's a form of panick attack and can be very stressfull for viewers.

One of the characters has frequent panic attacks which he believes are asthma attacks.

It's very overt and the character is mocked for it.

Eleven appears to be having anxiety attacks several times after she rips off her blindfold

Character gets anxious about being caught doing something, character gets anxious when faced with the prospect of lying, debatable whether they're anxiety attacks but it can be intense for some people

Someone *Uhm natsuki* vomits, and becomes SUPER frantic when she finds Yuri's body. Also Yuri gets a little crazy when you read her last poem.

A small child has a seizure due to fear/anxiety

An episode is dedicated to helping Connie deal with negative thoughts. It’s a happy ending.

Dean has flashbacks. Bobby has a panic attack in one episode.

Chidi, one of the main characters, has anxiety and is often shown panicking

Spider man has a major anxiety attack during a fight where he’s psychologically attacked and is trapped in a kind of hell

Also dissociative disorders and other symptoms of anxiety are shown.

Certain characters are shown panicking, especially Sayaka.

Graphic panic attack in the ep 1 intro (around the 2 min mark), when Rue is a child, and later the same episode at the party Rue talks explicitly about a panic attack just after the 40 min mark (pretty short scene though) - could be others, haven't seen every ep yet

A character is shown having anxiety attacks multiple times throughout the movie.

Dani has several panic attacks brought about by seeing her specific ghost. She hyperventilates, cries, and overall is having a very bad time.

Webber has an anxiety attack that he thinks is a heart attack, characters are shown having panic attacks and flashbacks frequently.

Syd, the main character has anxiety attacks frequently throughout the series

A character with PTSD panics when hearing loud noises and talks about the war.

Adora has anxiety attack nightmares/night terrors whenever she sleeps. I do wonder if it’s an imitation of ptsd because she can’t calm down/relax and is always on hyper alert.

A woman begins to panic after she believes she is going to die

S1E1: BoJack has two anxiety attacks. S4E10: BoJack is shown lying on the floor panicking. S6E8: Hollyhock has an anxiety attack at a party but grounds herself. S6E14: Todd’s mom has an anxiety attack.

in what episodes?

I'd say there are. Characters are shown to heavily panic, scream, become incredibly agitated, and semi-shut down.