1.3.2 Addiction as a Brain Disease/Disorder.

Topic Progress:

In order to define something as a disease, three conditions need to be present. There needs to be;

  1. A specific location in the body
  2. A specific dysfunction within that part of the body
  3. A specific set of symptoms that marks this illness as distinct from other illnesses

With addiction all three of these are well known. Firstly, as ASAM and NIDA make clear in their definitions addiction is a brain based illness. This is sometimes difficult for people to accept because they can’t see it. We can only see what’s happening on the outside. we can see that addicted people’s behavior is out of control, and the physical signs of them getting sicker, such as overeaters who have become obese, alcoholics who have liver disease, or injecting drug users who have blood borne viruses. What we can’t see is the thing that’s causing them all to behave this way, because that’s on the inside.

To get really specific, addiction is predominantly a limbic-brain illness. The limbic brain is an ancient part of the brain that regulates basic instincts and survival drives. Think of it as the ‘emotional brain’ or ‘animal brain’. The part of the limbic-brain that is dysfunctional with addiction is a group of brain cells that are connected by a pathway called the reward circuit. The reward circuit also influences other limbic-brain functions like motivation, memory, and learning.

As well as the limbic brain, addiction also affects another more recently evolved brain structure called the cortex which is sometimes called the ‘mammalian’ or ‘human’ brain because it only exists in mammals and is only highly developed amongst the higher mammals likes apes (including humans). The cortex regulates things like decision-making and impulse control.

The reward circuit begins in the limbic brain and works its way up to the cortex. A good way of thinking about addiction is to imagine the older, instinctive animal brain gaining the upper hand over the more newly evolved, rational human brain. As addictive behavior progresses these brain regions stop communicating with each other and the ‘animal instincts’ take over.

This brain malfunction (non-communication between limbic and cortical brain structures) causes some of the external symptoms of addiction that we all know so well:

  • Compulsive reward seeking
  • Impaired decision making
  • Dysfunctional emotions
  • Inability to stop despite harm