I'm just going to jump right in here: I was recently diagnosed with depression, and I'm having a really hard time dealing with it. But that's not the point. The thing is, in the process of receiving the diagnosis, and going through therapy, and seeing 800 doctors, etc etc, I've kind of been ignoring my friends. In my current emotional state, it's really hard for me to want to do anything social (or really anything in general) whatsoever, but my friends can't respect that. This is partly (or probably totally) because I haven't told them about my depression. My question is, how do I break the news to a few select people without seeming like an attention-seeker? It's a really personal issue, so I don't even necessarily want to tell them, but I feel like I have to in order to clarify why I've been acting the way I have. Before therapy, I suppressed everything, but lately the floodgates have been opened and it's obvious that something is up with me. It's going to be hard to avoid the topic any longer. Talking to my parents about it was hard enough, so I'm scared to discuss it with my friends. Besides, I don't want to put them on the spot or make them feel as though they have to comfort me or fix my problem. At this point, only a professional and medication can do that. I just want to deliver facts. Help?
I'm sorry you're in this situation, Sparkler. Normally, serious-type questions go to Auntie, perhaps because the higher-ups realize that my advice boils down to "boys are stupid" or "I don't know the answer because I am a stupid boy," but I'll try to field this one as best I can. I'm actually kind of suited to it, because I've been on both sides of this situation—the depressed guy, and the guy a depressed guy tried to talk to—so I have an idea of how you're feeling.
Although, truthfully, I couldn't afford to be technically diagnosed and treated for clinical depression—all I did was go to a psychiatrist friend-of-the-family, and he covertly handed me a Ziploc bag full of orange mystery pills, so I'm not sure what that makes me, except perhaps an accessory to a felony. My off-brand Zooloft or Depress-Away or whatever didn't help, and nor did anything else, except the passage of time. The point is, I don't expect to be able to logic your depression away using statistics—statistics like "tons of teens suffer from depression" and "statistically, puppies are amazing." But your friends might think they can defeat your brain chemical imbalance with superior logic, which is why you have to:
Prepare for them not to understand.
A lot of people still think "I have depression" means "I feel sad at the moment." They might point out that, but, there's a rainbow outside! Maybe they'll politely remind you that you have a nice life, and logically shouldn't be depressed, because it's not like you're starving in some impoverished war zone. Of course, people who are starving in impoverished war zones are often much less depressed than we are, because Brain Errors don't adhere to simple logic, but don't expect your friends to know that.
I would say that you should know what you want from them before talking to them, but you seem to know already: you're not asking for their comfort or attention, just for them to understand what's up with you. I actually think asking for comfort and friendliness might help—even if all they do is e-mail you YouTube videos of a ferret that gets lost inside a cake—but you know your friends better than I do. Just prepare for the possibility that, when you deliver the facts of your situation, those facts don't quite take.
Pick a best or closest friend as a sounding board.
It's easier to just talk to one person first—either to test-drive your explanation, or because you expect her to communicate it to everyone else. You certainly don't want to wait until all your friends are together, joking around, and go "GUYS I HAVE THE DEPRESSION," and let that sentence hang awkwardly in the air, like underpants on a space station. If there's one friend you're really close to, he or she is the one most likely to know that something has been wrong with you lately, and least likely to say "But how can you be depressed when there is such a thing as baby porcupines??" And even if this friend doesn't get it, if you two are close, you'll be comfortable saying "shut up shut up shut uuppp" as she emphatically describes a porcupine eating bananas, at which point you can explain that your legitimate medical condition cannot be solved by any possible number of porcupines.
Decide how to say what you say.
The goal here is to establish the seriousness of what you're feeling without seeming like you're walling in emo-ness and just looking for positive attention. Start off by saying "I need to talk to you about something serious," instead of just going "Hello I am depressed," because then she'll just go "Ha ha me too" and start talking about... you know, hobbits or something.
Once you have her attention, say something like "I've seen some doctors, and I've been diagnosed with depression." I know that's sort of wordy, but you need words like "diagnosed" to communicate that this is a freaking medical condition and not a case of The Sads. At this point in your life, your brain does not work. I personally guarantee that it will work, eventually, but right now it doesn't, and it's important for your friends to understand that this isn't just a passing mood. What you say next is up to you, and up to how your friend responds, but you don't want to be too overwhelming. If she's completely supportive, then, as you said, open the floodgates. It will feel good to be honest, if the situation allows it. But if she doesn't know how to react, dial it back. This can unfold over several conversations—the only goal, initially, is to articulate why you've been so different lately, and to let her process that.
I got a depression-related question a long time ago, and the one thing I really wanted to stress to the letter-writer was that time really does heal all wounds. Just listen to some extremely pretty music and believe me that, whether or not your friends are able to be supportive and understanding, nobody stays in the place you're in forever; you will get better.