I can't really relate to it. I've always been an oddball when it comes to music, usually choosing instrumental and soundtracks over music with lyrics, with a few exceptions. I never really connected with lyrics and found them to often be very similar in meaning. I guess I'm not poetic enough, but what I love the most is melody. I haven't had any withdrawal symptoms before. Sometimes I've gone days or even weeks without listening to my chosen tracks when busy or on holiday, often even forgetting about it.
I'm sceptical of physical side-effects, so until I find a paper of a real scientific study on this I doubt I could believe it. Music is an entertainment medium like films and TV, and even those have soundtracks of their own which add to the entertainment value and play a key role in keeping our attention. But I never hear about people having withdrawal symptoms from visual entertainment, again highlighting the fact it contains audio which would produce the same effect. Then again, maybe some avid anime watchers here would beg to differ...
I don't get people who mostly listen to music for the lyrics. But I suppose many wouldn't understand my enjoyment of music almost purely for the instrumental side. It's really subjective. To me, I connect with melodies on an emotional level, especially with soundtracks as I think back to the scenes they're played in. Usually when people get soundtrack CDs they do so for songs from openings and endings (often in the case of anime) or a main theme, whereas I mostly care about background music. The Outlaw Star opening and ending tracks (Through the Night, Hiru no Tsuki and Tsuki no Ie) are the most popular on my YouTube channel, but I usually don't listen to them as I don't feel as much of a connection. I guess this is pretty off-topic, but it's something I've often wondered about and I've never really found the chance to ask people why they think the lyrical music is so much more popular, especially since Outlaw Star has such wonderful background music.
Is music addictive? I guess so, like any entertainment medium can be. I'll look up any studies on withdrawal effects when I have the time.