Parentheses are generally used for further explanation. Without it, the sentence structure is still complete, and parenthesis does not affect the sentence trunk.

The main point of this sentence is that she was stumped by something called "social therapy".

Why is there a comma after it? Because it's parentheses. So here seems to care about the back, but it doesn't matter. It's just a supplement, which means she said it.

The panacea is so powerful that it can help you quit smoking, lose weight and get rid of poverty. Overthrow the dictator. It's appositive. It can help you quit smoking, lose weight and get rid of poverty. Overthrow the dictator. It is the attributive clause that modifies the panacea. The backbone of this appositive is a panacea.

Then the whole sentence is. She stumbled upon something-such an effective panacea.

There IS no is here, but it becomes a separate sentence after adding is. take for example

The use of dashes is as follows, and here is the sixth one.

Some usages of English dashes;

1 Used to express or highlight appositive words.

Used to summarize some of the things listed above.

Used to express hesitation or hesitation.

Used to express a sudden change of meaning.

5 is used before the quoted sentence (instead of a colon or used with a semicolon).

Used before an explanatory clause or sentence.