I can testify that poorly developed Si and Fe can create major addiction problems for INTPs. Tertiary Si filters the world in a highly limited, selective way, which creates the potential to fixate on few sensory experiences we come to rely on and expect. My very narrow capacity to focus on my environment makes easily procured sensory comforts, like junk food that doesn't require preparation, extremely attractive. I don't want to have to prepare or worry about these things, and this tunnel vision can be especially bad if it becomes engaged with some Fe attachment. Just like how mature SJs live in habit without stepping back from it and considering the value of their cherished pastimes, the SJ shadow can attach us to routine, but in being less developed than that of our SJ counterparts, it is more likely to be a more primitive, unrefined routine that pops up to meet some urgent emotional contingency.
During stress, for instance, I'll stockpile a massive amount of my favorite snacks and just graze on them throughout the day. I think it is important to understand this in the context of the SJ shadow, since it seems that for other types with an SP shadow, like the INTJs I know, addiction manifests as more a process of liberation from boredom, while for SJ shadow manifests it as a way to externally regulate a powerful, chaotic inner process of thought.
As far as NTs in general, I doubt that we struggle with addiction more than other types on account of anything intrinsic in our typologies, but probably are more likely to be depressed than other types which manifests itself in addictive behavior. Plus, we are probably less likely to be aware of our addictions or their triggers due to a lower level of emotional consciousness than, say, our NF peers, thus making them more deeply entrenched. Sometimes I'll look back and only later understand that I went on an internet or food binge to avoid or comfort some emotional reality, while somebody with better developed F would probably at least be aware of the root of this compensatory behavior even if they still choose to indulge in it.