If you were under medical treatment for your depression (hopefully you were), just say that you had a medical issue, the treatment helped you recover, and that

If you were under medical treatment for your depression (hopefully you were), just say that you had a medical issue, the treatment helped you recover, and that you spent part of the time recovering studying independently. Be prepared to provide a note from your therapist/doctor that provides the dates you were under treatment to back up your words but note it does not have to describe the issue you were treated for or the treatment. If pressed about the specifics, know your rights (Google around for info on what employers are legally permitted to ask about medical conditions), remind them of those restrictions, and be prepared to write off that employer if they persist. Resign yourself to the fact that you're going to have a long, difficult road ahead if you want a programming job. Being from a non-traditional background, you're going to really have to shine at the interpersonal and coding side of interviews to persuade a company to hire you. Use study guides for both aspects and try to attend local tech meetups where you might be able to persuade a working professional to give you interviewing tips. Persistence almost always pays off. Good luck to you.