Yes, I definitely would call it an addiction. Or at least a compulsion. I have gone a year plus 24/7 and it definitely got less...desperate?
But whenever I am enduring life stress and haven't worn in a while, it starts with perusing ABDL tumblrs for a week or two, then being active on Reddit, then progressing to full-on, every-night diaper dreams and looking up prices late at night. This urge comes from nowhere. I'm not even in the mindset like "Oh, I'd like to wear" when this pattern starts. Matter of fact, nowadays I get really content with an unpadded life -- being as physically active as I am. I purposefully wear about 18-24/5 now because I realized that I just don't do good without diapers. I guess you can say I have entirely given in to the addiction. I could not rid myself of it, so I learned to let it coexist in my life in a *healthy* way (I can't stress that enough, it was so unhealthy for so long)
TL;DR- It IS an addiction, but as long as it stays healthy, and you're still tending your other gardens, then it's a pretty great one to have as far as addictions go.