Ok first question.
What is your diagnosis ?
Second Question - who diagnosed you?
If it was a family doctor thats not a diagnosis its at best a guess but I wonder what you consider a full diagnosis?
A psychiatrist will talk to you, they may or may not use the 20 question test (many do as a first step though I hate it) then look at your history and your symptoms and make a diagnosis based on that, there are not all that many blood tests or other tests for many mental illnesses and brain imaging is not really much use in most mental illnesses - its usefull for neurological problems but depsite what the many companies who do this (oh how I love the US health profit system) claim and the hopes of so many its not really producing any real results or conclusive diagnosis and for a chemical imbalance theyre going to be pretty much useless.
You say you have a history of depression? Well this history alone will exempt you from military service (and if that is hard to understand you might want to consider why giving someone with depressive episodes a weapon is a bad idea) and police and a lot of other jobs - mental illness is a killer for these for very good reason (refer to previous comment vis a vis weapons).
Sadly if you have a mental illness or a history of depression you may hjave to choose another career, this is normal for all of us and it ***** quite frankly (ask me about adoption sometime and I might be able to maintain composure long enough to explain how that feels)
There are 3 questions you need to answer to yourself.
1. Do i suffer from depression
2. Does this get better when I am medicated
3. Is my goal realistic based on 1 and 2.
If you can answer no to 1 and 2 and get a diagnosis confirmed that you are not suffering from a mental illness then go and chase the dream but remember that if you are wrong or try to hide it and bluff through the process it may hurt more than your career.
I have seen 6 psychiatrists in 15 years. Initial diagnosis was major depressive disorder. Most recent diagnosis is Bipolar II. I have been steadily on medication for around one and a half years now without improvement. Initially I was on Lexapro, gradually increasing from 10mg to 30mg over a six month period. As a mood stabilizer I was given Lamictal, again gradually increasing from 50mg to my current dose of 200mg. I have seen 3 different psychiatrists in the last year alone and every single one suggest some new medication. The antidepressant has since changed from Lexapro to Cymbalta and now Effexor (75mg). My moods have been much notably irratic on the medication and I am prone to crying without reason when alone. I only sought treatment again in 2006 in the first place because I wanted a good foundation for the crappy job (complaints in retail) that I was promoted to. I thought that an antidepressant and mood stabilizer would assist me in keeping issues in perspective. I have a habit of taking other people's problems to seriously and get upset that I cannot help. I understand that it takes many weeks before medication can be effective. Do I have to start over in self evaluating the effectiveness every time my dose is increased or changed? I see my psychiatrist every 2-3 weeks and the dose is always increased. Again I am just frustrated. I HATE having this label over my head all the time. It would be different for me if I felt better, but I don't. If things go bad, sometimes I get sad. If things go well, I'm happy. Sometimes I become energized by a new idea. Sometimes I make bad decisions in relationships and finances, but who doesn't? I can see why they would not want to give someone prone to depression a gun, but when I read the anonymous posts of soldiers who did get in, I don't understand why there isn't a place in the military for me too when I want to serve.