- [Instructor] As it turns
out, only a very small number of substance users
become substance abusers. And this is something
that we really don't know too much about. We don't know why certain
people, but not others, move from use to abuse. And we don't really know how use generally progresses to abuse. But even though we don't
have a complete model, we do have a number of
theories that pertain to this. And that's what I want
to go over in this video. The first model I want to talk about is the common syndrome theory, which is also sometimes called
the problem behavior theory. And this theory revolves around the idea that maybe there is one,
single underlying factor, a drug use propensity,
that might put people at a higher risk for abusing substances. But this is really deterministic. It kind of implies that anyone
who has a drug use propensity will develop substance abuse problems, and that seems pretty severe. A more nuanced way of talking
about this is to use what researchers sometimes refer
to as the Swiss cheese model. So here we have a piece of Swiss cheese, and of course it has holes in it. So imagine that every individual on Earth is a unique slice of Swiss cheese. So the placement of holes
on each individual slice and the size of these holes
and the number of holes vary from person to person. And so we can imagine that
the solid parts of the cheese represent things that can
protect us from substance abuse. And so the more solid area you have, the less likely you are to use substances. The holes, on the other
hand, represent risks. So individuals with many holes,
or with really large holes, would be at a greater
risk for substance abuse. So maybe we can imagine someone whose friends use substances, and that opens the door
for their use as well. Or maybe they have a relative with a substance abuse problem. And in fact, there are
many different types of risk factors for substance abuse. And we can think about
these different risk factors as being individual slices. So let's say that we have three
slices of Swiss cheese here. And each represents a
different kind of risk factor. So we have biological risk
factors, things like genetics. Psychological risk factors, so maybe certain personality factors that are correlated with addiction. And we also have social risk factors. Things like having friends
who use substances, which we talked about earlier. And of course, these slices are different for each individual person. They might have more holes
in one and fewer in another. But everyone has some unique
combination of risk factors. So now let's try to use
this as a way to talk about why some individuals develop
substance abuse problems and others don't. And to do that, I want you to imagine that you're shining a laser pointer through these different slices of cheese. So I have three laser pointers here, and these laser pointers represent substance use for different individuals. And if the light hits a piece
of the cheese, it'll stop. But if the light goes through a hole, it will continue to move forward. And it is only when the
light reaches the back wall, only when it has passed
through all of the holes and in the right combination, will someone develop addiction. So let's say we have
someone who uses substances, but they don't have a lot of risk factors. They don't have a lot of
holes in their Swiss cheese. In that case, the cheese will
block the laser pointer beam. And the person will not develop addiction. But let's say that we have someone else who does have some risk factors. Maybe they have a relative who has a substance abuse problem. In that case, some of the
light will get through. But if they have fewer holes
in their other Swiss cheese slices, or if they aren't lined
up in the correct pattern, then the light will stop there. But imagine we have someone else, and maybe they have a lot of
holes in their Swiss cheese, they have a lot of risk factors. Or maybe they have an average amount, but they're lined up in
a very particular way. In this case, the laser will
be able to shine directly through the holes of the Swiss
cheese for all of the slices, and will illuminate the back wall, meaning that that person
will develop addiction. And hopefully I didn't
confuse you too much with this laser pointer
Swiss cheese model, but the takeaway's that
each individual person has a unique combination of risk factors or things that will make them more likely to abuse substances. And while a lot of individuals
might use substances, substance abuse problems will only develop when these risk factors line up. So when they're combined with
each other at the right time.