The Nature of Addiction

 

Brain-circuits

Amy Winehouse was a terrific talent and one of my favourite recording artists. She also struggled with substance abuse. To what extent remains largely unknown but her death has fueled debate as to the precise nature of drug addiction and how it should be addressed by society as a whole.

In other words, why do some people behave in the often self-destructive manner in which they do? And why are people addicted to drugs in the first place?  How, if at all, might they be helped?

Now, you might think that this is a spectacularly hard task to delve into the neuroscience of addiction to try to shed some light. Surely, drugs of abuse (such as amphetamines, cocaine, opiates, and alcohol) have a broad range of actions that are dissimilar from each other? Well, that is partly true, but when it comes to their addictive properties, they have more in common than you might think.

 

What Constitutes Drug Addiction?

Drug addiction, as most will know, develops as a result of chronic exposure to a particular substance. People who are addicted to a drug show similar patterns of behaviour. These include:

1. A compulsion to seek the drug

2. An inability to control the amount of drug consumption

3. A negative emotional state when subjected to periods of withdrawal

Neuroscientists have sought to understand the neural mechanisms underlying these behaviours for generations and emerging from these studies is the concept of the ‘reward circuit’ that seems to be involved in the development and maintenance of drug addiction.  In fact, research on the brain may be entering a golden age of discovery.

You see, the brain behaves a little bit like a factory with different departments responsible for producing a certain sort of feeling or behaviour. This means that there are distinct areas that are concerned with happiness, memory, movement and so on. This is, obviously, an oversimplification, however, it is useful to think of the brain in this way particularly when analyzing how brain circuits are altered as a result of drug use.

The Reward Circuit

The reward circuit consists of several brain regions that are heavily interconnected; each with distinct – but related – functionality. Dysfunction in each of these areas has been implicated in problematic drug use.

 

The Nucleus Accumbens: Pleasure Center

Now, the nucleus accumbens is known as the pleasure centre of the brain. This can be a result of taking drugs of abuse, or simply eating, engaging in sexual activity or indeed anything associated with pleasurable reward.

All drugs of abuse raise the level of a chemical known as dopamine in the pleasure center and it is this elevation in dopamine that is responsible for the feeling of euphoria associated with drug intake.

 

The Amygdala: Fear

On the flip side of the coin, the amygdala is a region of the brain situated right next to the nucleus accumbens, but is often associated with feelings of fear and anxiety.

As opposed to the positive reinforcement created by the pleasure center, it is during “withdrawal” that the amygdala seems to have its largest role. Basically, as access to the drug is taken away, stress-related hormones are increased in the amygdala, which can lead (at least partially) to the negative feeling associated with withdrawal.

 

The Hippocampus: Memory

The hippocampus is an area of the brain that is associated with learning and memory as well as the ability to perform tasks requiring navigation, such as finding your way around a building.

Activation of this memory center of the brain is implicated in initiating “cue-induced” drug-seeking behaviour. Indeed, it has been shown that “cue-induced” craving of drugs (e.g. the feeling of needing a drink in a pub or a cigarette with a cup of coffee) is associated with an increase in activity in the hippocampus (as well as the amygdala) in humans, indicating that normal memory function may be being encroached upon by drugs of abuse.

 

The Prefrontal Cortex: Decision

The prefrontal cortex are often described as being critical in carrying out decision-making, a process known as executive function; the activity of decision making is extremely disrupted in subjects who are addicted to drugs. This may go some way to explaining why drug users often make poor decisions regarding drug intake (e.g. pursuing a drug whilst fully aware of the negative impact drug intake will have on them and the people around them.)

 

What Goes On In The Brain Of A Drug Addict

So…

As complicated as this may have sounded, it represents a general idea of what actually goes on in the mind of a drug addict. In other words, drugs mess with your head. If you or anyone you know is struggling with an alcohol or drug addiction, click here or call Cory at: 604.818.1771.