Personally, I feel that the following types of questions are off-topic, when no framework or background is given by OP:

• Has X been studied?
• Is there literature on X?

With X being a disease / drug interaction / brain processes etc.

These types of questions are imo off-topic, because they require an extensive literature search for a proper answer, or they can be answered with Yes! Here's a paper Y!'
With Y being the top single paper out of 100k hits on Google Scholar.

The former approach requires hours of work (we're not here to write a review paper for you), the latter can draw in a 100k answers :)

However, with a proper framework, and with background research focusing your question, these types of questions are on-topic and warmly welcomed. For example consider

https://cogsci.stackexchange.com/questions/12969/how-do-mammals-estimate-the-speed-of-moving-objects/17127#17127

Here, OP starts off superbly broad (speed estimation in the visual system), but then focuses the question on a particular process (top-down effects on speed estimation), concluding the question with a specific example. This type of question is great.

Personally, I feel that the following types of questions are off-topic, when no framework or background is given by OP:

• Has X been studied?
• Is there literature on X?

With X being a disease / drug interaction / brain processes etc.

These types of questions are imo off-topic, because they require an extensive literature search for a proper answer, or they can be answered with Yes! Here's a paper Y!'
With Y being the top single paper out of 100k hits on Google Scholar.

The former approach requires hours of work (we're not here to write a review paper for you), the latter can draw in a 100k answers :)

However, with a proper framework, and with background research focusing your question, these types of questions are on-topic and warmly welcomed. For example consider

https://cogsci.stackexchange.com/q/12969/6983

Here, OP starts off superbly broad (speed estimation in the visual system), but then focuses the question on a particular process (top-down effects on speed estimation), concluding the question with a specific example. This type of question is great.