Your favorite team just won the trophy, and you can barely stop screaming out of delight. You lost your mom and had an uncontrollable outburst of emotion. You don't choose the hysterical voice. It chooses you, and you can only hope it comes with extreme happiness.
The hysterical voice is like a marathon of emotion. It is intended to show an unbalanced, sometimes uniquely large set of feelings within a short uninterrupted spell. Still don't get it? Think of Joaquin Phoenix's portrayal of the Joker in the movie 'Joker (2019)'.
Hysterical voices bring thrillers and horror movies to life. The characters are often confused about what emotion to express at that time, and end up expressing all the emotions as intensely as they can in short bursts. This voice would be perfect in plays where you have to portray strong feelings of devastation, delight, or even both.
Think of a high-pitched repelling cry or an insane laugh. The confused concoction of extreme emotion, showing momentary or sometimes full-blown insanity. A hysterical voice can be disruptive in unexpected moments. It can also be used in both moments of happiness and sadness. It is especially effective in showing a character’s confusion between two extreme emotions. The one thing it is not, is silent.
The hysterical voice is imbalance and is mostly used to portray psychological torment when a character cannot control their emotions. It can also be used to show a character turning crazy, and works perfectly when you have to portray a sense of urgency.