- [Voiceover] Let's consider drugs.
I'm also going to call them substances.
And as you know, there's a whole bunch of
different drugs and substances that people use.
Some of the most common ones include
alcohol and tobacco.
But also there's a range of other ones
including cannabis, opioids.
That includes things like heroin.
Also things like stimulants.
And that includes things like cocaine and amphetamines.
And a whole bunch of other things
including hallucinogens.
And that includes things like LSD,
inhalants, hypnotics, sedatives and other things.
And let us not also forget one of the most
commonly used substances, which is caffeine.
Commonly found in your mug of coffee or tea.
So when we look at drugs; when we consider drugs
there's several things that we have to also
kind of look at.
So we have to consider what happens
when drugs enter the body
and also what happens when they exit.
And these are two different processes.
The first process when the drug
actually goes into a human body,
we can actually call this "intoxication."
And that's when the drug exerts its effect on somebody.
When it goes into their body.
And if it exits after a period of prolonged use,
we may experience something called "withdrawal."
So what are we talking about when we mention intoxication?
We're talking about both the behavioral
and psychological effects of the drug on the person.
And these can be very much drug specific.
So can we think of some examples of intoxication?
Well, let me give you a couple examples.
When we're "drunk,"
that's an example of intoxication with alcohol.
Or when we describe somebody as being "high"
that again is a lay, colloquial way of describing
what someone is intoxicated with another substance.
Which may be something like cocaine or heroin, for example.
So what about when a substance actually exits a person?
Well withdrawal happens when we stop a substance.
Stop taking a substance
after having taken it for a prolonged period of time.
And what happens there is that we get withdrawal symptoms.
Symptoms of stopping the drug.
And these symptoms can make us feel quite sick or ill.
And in some cases can be quite dangerous
or potentially fatal depending on the drug.
And when I say "drug" I should also say "substance" here.
That's a more formal way of referring to it.
And both intoxication and withdrawal,
the effects really vary on the precise drug
or substance that we're using.
But let us also think about drugs,
or the substances, in a different way.
Let us think about them on their effects on the human brain.
Well we know these substances can actually result
in a whole heap of other conditions.
Because they can result in something called
"substance-induced disorders."
So these are conditions
that are actually caused by substances.
And these are conditions that could be
substance-induced mood disorders.
Disorders of mood,
either experiencing moods that are too high, like mania,
or moods that are low like depression.
Disorders related to anxiety,
sleep, sexual function.
We may also get problems with something called "psychosis;"
which is a loss of contact with reality.
And that's where people can hear voices,
or see things, or become very paranoid.
Now when these drugs affect the brain,
something completely different may also happen.
We can actually have the development of
a "substance use disorder."
Now, not everyone that uses a substance
develops a substance use disorder.
Which basically implies that when they use this drug,
the way that they're using the substance or the drug,
is causing them a real degree of impairment.
It's really affecting the way that they
function in their life.
Whether that's at school, work, or home,
their drug use is really impairing.
Now let us talk about
substance use disorder a little further.
Because when we talk about substance use disorder,
the main issue that we are looking at
is that there is a problem here.
There is a problem with their substance use.
And, again, not everybody that drinks alcohol
or smokes cigarettes, or uses other substances,
not everybody has a substance use disorder.
But, some people do.
So let's have a closer look at this.
So how do we know they have a substance use disorder?
One of the ways that we can find out
is by looking at their use.
And it's really important factors
that we need to consider here.
Are they using increasingly large amounts?
Are they experiencing increasing craving
or strong desires to use?
Are they spending more and more of their time
recovering from or trying to get the substances?
Are they failing to try in cut back or cut down?
And also feeding into this use issue,
are they experiencing problems related to
their obligations at work?
At school? At home?
If these things are appearing
that really does suggest that maybe there's a problem,
and maybe they have a substance use disorder.
A second factor that we look at apart from use
is the presence of something we talked about earlier
and that was the presence of withdrawal.
Now this is something that happens after
you stop using the drug after prolonged or sustained use
and you get-- you can feel pretty sick or unwell,
with different symptoms depending
on whatever drug that you're using
after having stopped the drug.
And this really also suggests that physiologically
that you're dependent on the drug.
Your body's dependent on the drug.
And withdrawal can be dangerous.
For example, alcohol withdrawal.
You can get seizures potentially and die.
And withdrawal symptoms are specific to their substance.
So again, the presence of withdrawal
suggests that you have a problem.
Finally, the last thing I want to mention
is the presence of something called "tolerance."
And what tolerance is,
let me graph it out for you.
If this is the effect and this is the dose,
the effect, the effect of the drug
decreases with subsequent doses.
Your body adapts to or builds a tolerance to the substance.
So what people do in order to overcome this tolerance
is they tend to keep increasing the dose,
or the amount, of the substance that they use
in order to achieve the same level of intoxication.
So as we can see, the way that people are using
and the problems that they're encountering
with the substance,
development of withdrawal symptoms
and the development of tolerance
all suggest that we have a problem.
And actually just having a couple of these
such as craving, or withdrawal,
or having using increasing amounts,
not being able to cut down,
is enough for us to be able to diagnose
a substance use disorder.
And there's different severities of substance use disorder,
from mild, moderate to severe.
The one caveat I would say is that
caffeine, of all the drugs that I've mentioned,
with caffeine we cannot develop a substance use disorder
according to the current criteria.
Now that may be an arbitrary thing
but I just want you to know that.