The Addicted Brain Flashcards
(16 cards)
What is addiction?
Repeated behavior that results in distress or has a negative impact
Drug addict versus drug abuser
Addiction implies a more serious problem than abuse
Drug Dependence > A state of physiologic need such that physiological signs occur when you stop taking the drug.
DSM-5 > The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, in which problematic use of drugs is being referred to as
Substance use disorder (Continued use in spite of problems)
Substance induced disorder (Refers to things caused by the drugs, like intoxication/ withdrawal
Addiction is a brain disorder
Brains are affected (chemical changes), and often help maintain the addiction.
Drugs are not a temporary fassion.
Cocaine/ tabacco / ayahuasca/ wine through history were all used to connect with spirit.
Animals also like drugs.
10 classes of drugs
Alcohol
Tobacco
Cafeïne
Marhuana
Inhalance, glue, gascoline, 3rd world countries
Opiates (painkillers)
Anti anxiety medicine
Stimulates (cocaine)
Hallucinaties (LSD)
Other
Side effects
- Loss of control (phsycological)
- Toxicity (physical)
Alcohol > Liver disease, also withdrawal can cause seizures
Prefrontal Cortex, grey matter volume is way lower with Alcoholic patients.
Marijana > Decreases metal and physical performance
Substance Use Over Lifetime
Alcohol > 82.5%
Tobacco > 68.8%
Marijana and Hashish > 42%
Cocaine and Crack> 18.3%
Hallucinogens > 14.8%
Prescription Painkillers > 13.8%
For drugs to get in the brain, it has to go to the blood. A large fraction of the blood from the heart, goes directly to the brain
How is this process with different types of drugs?
Drug Absorption
* Oral - Absorption of drug from stomach/ intestines
* Intravenous - Injection
* Inhalance - absorbed from the air in the lungs
Drug Metabolism
Enzymes modify the structure of drugs often making elimination more effective
This usually takes place in the liver
It can be a very complex process
Drug Elimination
Drugs are removed from the body mainly in the urine or feces
Clearance > a measure of the bodies efficiency in eliminating the drug
Elimination half life > How long it take for drugs to be removed for 50%
> often for a drug to be completely removed from the body, it takes 5 half lives.
When a drug needs to be absorbed through the stomach, first it will slowly build up in the blood, and after its peak it will go down.
This can all go in a steady rate and a fractional rate.
Drug screening/ test
Screens > Looking for different types of drugs in urine
Antibodies will attach to a drug because of the shape of a molecule. Multiple drugs can be detected by adding a secondary antibody with a label.
Detecting drug in urine depends on various factors (how well was the drug absorbed/ does the individual have a compromised metabolism/ etc)
A screen may focus on detecting a metabolite because it may have a longer half life. For example, Cannabis Metabolite can still be in the blood up to 60 days.
Tests > Looking for a specific type of drugs in the blood
After a screening one might want to do a bloodtest, to get very reliable results.
Synaptic Transmission / Neurotransmission
Neurtransmitters set off signals that is very import for the brain and our evolution. Every thought, sensation, emotion or idea, sterns from there.
Nerve cells / neurons exist of:
1. Cell Body, here is where a nerve impulse usually starts.
2. Nerve Terminal at the end of the Axon through which it connects (not physically) with other neuron dendrites > release of neuro transmitter.
3. The Nerve Terminal releases substances called neurotransmitters. These bind on the receptors of another neuron. Which can cause activation of that neuron as well, and so forth. Neurotransmitters will temporarily fly around between the neurons > receptor interaction.
4. Until the neurotransmitters are being taken back by the Nerve Terminal > removal of receptor.
Axons can be very long, so neurons can connect with other neurons that are relatively far away.
The whole process can just take milliseconds.
Drugs work by altering neurotransmission.
Examples of Neurotransmitters:
Dopamine
Serotonin
Acetuylcholine
Enforphin
Which neurotransmitter will be used by drugs, depends.
What are vesicles
But after synthesis, after they’ve been made, neurotransmitter molecules have to be stored in a protected way and away from receptors. We don’t want stray neurotransmitter floating around the brain setting off signals. For that reason, neurotransmitters are stored in vesicles inside the nerve terminal.
When an action potential or a nerve impulse invades the nerve terminal, the vesicles fuse with the membrane of the nerve terminal and release their contents into the synaptic space.
How does cocaine work in the brain
Cocaine blocks the transporters, through which released dopamine is normally being transported back into the nerve terminal. The result of course is a lot of dopamine in the synaptic gap between the neurons and a lot of receptor stimulation.
How does Nicotine work in the brain?
Acetylcholine is related to the drug Nicotine.
when acetylcholine binds to the ion channel receptor, the channels open, the ions flow, and the neuron is affected / excited.
Acetylcholine, is removed from its receptors by being broken down, literally destroyed. by an enzyme, acetycholinesterase, into acetate and choline.
Neither acetate nor choline are activate receptors. So the enzymatic breakdown of acetycholine yields inactive products.
What is the effect of drugs in general on the brain?
Because the level or presence of the abused drugs are under the control of the drug-taker rather than the mechanisms in the brain, receptor stimulation gets out of control.
Drugs have a very profound and long lasting effect on the brain. They terribly distort the process of neurotransmission. And that’s how they produce their dramatic effects.
How is it possible that a drug is multifunctional?
The shape of the drug molecule must be complementary to the shape of the receptor molecule. A common analogy is that they have to fit together like a key in a lock.
Because drug molecules have different shapes when viewed from different angles and sides, they can fit into different receptors.
