addictive "tendencies" and their carryover...
Granted, I am oversimplyfying a bit here....
What I think this topic ultimately comes down to is how much someone is susceptible to "addictive behavior"... i.e. "pleasure seeking behavior".
For example- A person get's bariatric surgery... the lose a ton of weight... what happens to MANY of them (NOT saying ALL of them)? They become compulsive gamblers and/or smokers and/or develop other "unhealthy" behaviors. Why? Through food, they were essentially altering, albeit temporarily, their brain chemistry. It's then through this compulsive eating/behaviour they are basically getting a "high" just like any other drug (granted, a MUCH smaller "high", but a surge in serotonin and/or dopamine, adrenaline nontheless). It's about the "reward center" of the brain being activated... but constantly.
So, as someone mentioned, jokingly, but they were right... exercise is "addictive"... it alter's one's brain chemistry. If you took that same person and restricted their workout's to zero... I would bet they would become "addicted" to something else... even the internet can be included in this... it's been shown to raise the "feel good" neurotransmitters.
The point about tyrosine- I see what is being said, but tyrosine more works as a precursor to the thyroid hormones and adrenaline (it has been used to treat depression)... if one were to take tyrosine supplementation out of their regimen, my bet would be they would either consciously or unconsciously find some other food/drug/behavior to elevate their mood.
So, with all that said... I think that's why steroids can be included... if a person has been on for a considerable amount of time and had everything stopped abruptly, I would guess they would probably find some other avenue to achieve the same kind of satisfaction... sometimes a "positive" one... but all too often, for whatever reason, they usually choose a "negative" one.
Edit: Plang wrote this as I was writing mine... I was basically given everything in that cycle by a client I train..is by far the most I've ever taken. I do have an addictive personality Please note Plang, I'm not quoting you to "knock" you sir, it was just helpful to my point... truth is, I would say I too might have an "addictive personality" or "prone" to addiction... thankfully, it's never been one of a "negative" route, BUT, honestly, I think it could if I didn't have my gaurd up enough.