Learn Spanish (Latin America): Dicen que las drogas son un problema grande.

In this sentence, Dicen doesn't refer to a specific group of people. Instead, it uses the impersonal third-person plural. It works just like the English phrase "they say" or "people say" when talking about a general rumor, opinion, or fact where the specific speaker doesn't matter.

In English, we can say "They say drugs are a big problem" without the word "that." Can I drop que here?

No, you can't. In English, dropping "that" is completely normal, but in Spanish, the conjunction que is absolutely required to connect the two parts of the sentence (Dicen and las drogas son...).

Why is it las drogas and not just drogas?

When you talk about things in a general sense or refer to entire categories (like "drugs," "love," or "cats"), Spanish requires a definite article (el, la, los, or las). English usually drops the article in these cases.

Wait, why is it un problema and not una problema?