Did you have a look at the slide deck? I don't design survey's for a living, but the questions seem carefully chosen (often included as a footnote on slides with graphs).
I just did; I was replying to your exact question in the comment. Questions like "Instagram can make me laugh when I am feeling down" do not look like the kind of questions that a good independently designed survey would do; in general, the would tend to be more of the kind that focus on a concrete event and their surroundings - it may look like they loose the perspective, you are looking at the only bad time that person had, but, done across a lot of people, it is more informative (would statistically represent the most likely state for the population, even if it is totally wrong for some individuals).
It's not showing me the 'reply' button on your comment.
That seems like fair criticism. It's not my area of expertise. I'm just here to post the source document because in light of what the study actually claims, the media reaction has been ridiculous.
Tangent: The “reply” link is hidden in some cases (fast replies) to avoid flamewars. If you insist on replying, clicking the date stamp to go the comment’s permalink will show a reply box.