Is the current "Ice Age' our most likely SHTF event?

It maybe a SHTF event for a few people but the chance is miniscule compared to driving a car or riding a motorbike!

So long as you and your family do not associate with druggies or the like the chances of you having a personal SHTF event are less than being hit by a meteorite!
Now if you have a druggie in the family you or your family are highly likely to suffer a SHTF event!

Whilst certain drugs are more addictive, the real 'addiction' is emotional not substance. The highs are more addictive because they offer a better escape from that person's pain, as science has show, the pain felt emotionally firing off the same regions of the brain as pain. The drug is a conduit in which that person feels 'normal' or at least not incredibly crappy. In a way it's self medication. The real cause isn't the drug, not everyone who does ice is addicted, but rather is often traumatic childhoods, either having things done to them that shouldn't [beatings for instance] or not having things that should have happened [neglect], often it's both. Those thresholds to a young child are much lower than people acknowledge or want to admit, yet the science is quite clear here. It's so evidential and so ignored. I don't work specifically with the drug addicted [or the other addictions, they're all the same really], though I do get it fairly regularly and with the kinds of people I get, typically it's an easy turn around because we work to repair the areas of trauma that they haven't dealt with. Mostly it's an education, that is give the person what they've been missing and whilst we identify their causes [to put it to rest] we also identify that whilst someone might have caused this pain, it is that person's responsibility in doing something about it. 

Unfortunately most people out there [and I'd include therapists] aren't very good at resolving people's early development with real finesse, aren't very good at connecting the missing love from their lives [hence the pain] that they ought to have learned about when they were in their early childhood [0-5] to be able to sooth their pain [as mentioned earlier similar to real pain for the subconscious]. This is one reason why numbing of any type is so appealing. The other thing I've noticed [applicable with ice] is that when people are missing love [depression] they can't get much done, to which ice at least initially seems to help a little. It's obviously a flawed pathway, it doesn't lead anywhere great.

So, no, there's no real chance of it being the foundation of a SHTF, it's no different at least in 'causation' from the other escapes, be it food, sex, video games, alcohol etc that have been a part of society for almost ever. If it were handed out free and from a tap at home for easy convenience, I still don't think it would cause SHTF, because most people wouldn't loose it. The reason is that they aren't seeking something to feel 'normal'. Think about it, would you use ice if you had free access to it, I sure wouldn't.

Is ice worse? It is in that it exacerbates emotional issues and it can trigger paranoia, delusions, and yes violence in some. As mentioned earlier, this is different from the main past drug of choice, heroin, which is/was sedative in nature. Alcohol also brings out violence in some and is much more prevalent, though alcohol is also sedative.  I've not got real data on this, though it seems to me that drugs bring out who people are.  If they're violent underneath their filters, then it brings it out, it takes away their hesitations on being violent.  Violence also has a well known cause, early childhood, as per the 'Adverse Childhood Experience' [A.C.E.] data, the biggest study [17,000] done.  So again, take care of the kids if you want to stop an 'ice age' *rolls eyes at the media*.  

We have zombies everywhere now, that is the missing emotionally connection and it's not the apocalypse. Ice isn't our main problem, how we treat our children is and slowly but surely that's getting better. One reason, despite what the media shows you, society statistically is safer and better all of the time. When the King of France fainted upon opening his window in the 17th century, because of the stench of crap in the streets, it's easy to see how we're living in utopia already. Making that better, I would argue through reason [truth and evidence], personal responsibility and taking care of kids is only going to make that better.  Ice a symptom of the disease, not the problem par-say.  As Aristole said 2000+ years ago, "we do not have knowledge of a thing until we have grasped its why, that is to say, its cause." 

I'm hardly an expert in security and from what I've read the consensus seems to be that security only slows down someone who is determined as well as working as deterrence to redirect them to easier targets. Makes lots of sense to practice what frostbite has described.

The dim view that police put on people defending themselves would probably get you charged *rolls eyes* if you're using a prescribed weapon even kitchen knives, if it did, this video is VERY important to understand.   [layperson's guess, not legal advice]

In Victoria it is complicated by the doctrine of self defense, which moves the onus onto the prosecution to prove otherwise. However the defence has to first convince the judge that there is a legitimate case for self defense. So it is not a true onus shifting.
Ie if you have time to evade ,escape call the police etc you instead get you legal fire arm and shoot the intruder you will find it hard work to convince the judge you are relying on slf defence.
A recent case in the media was a man shot an intruder from his bedroom at about 40 meters. He was convicted. Obviously a lot more detail but look it up as it is enlightening as to what you are allowed to do for self defense.
The crime act has a provision for a person to prevent or stop the continuance of an indictable offence. I think s.389. But it uses the reasonable man doctrine. And is not a blanket protection by any stretch.