Understanding self-harm, self-injury, and self-destruction

1. Alcohol (ethanol) enters the body through the oral cavity (i.e., the mouth). The inner surface of the oral cavity is mucosal tissue to keep the cavity lubricated and it is capable of absorbing alcohol into the bloodstream. This absorption is considered “insignificant”.

2. Alcohol flows down the oesophagus to the stomach where 10-20% of ethanol will be absorbed into the bloodstream. Alcohol enters the bloodstream via the mucosal tissue of the stomach wall, and travels straight to the liver. Alcohol can take 5-10 minutes to reach the brain because of the ethanol absorbed via the stomach. If you drink alcohol on an empty stomach, the pyloric sphincter [gateway between the stomach and the small intestine] is going to be more open, and the alcohol is going to immediately enter the small intestine after reaching the stomach. If food is also present in the stomach, the sphincter will open and close at a rate that allows food to enter the small intestine gradually, therefore if alcohol is also in the stomach, it will gradually enter the small intestine.

3. Alcohol flows through the pyloric sphincter into the small intestines where most alcohol absorption occurs. Human intestines are attached the to the posterior abdominal wall by a fold of membrane called the mesentery. Alcohol is absorbed into the mesentery via veins and then travels to the liver.

4. One function of the liver is that it detoxifies toxic elements into non-toxic elements before passing it to the heart and then the rest of the body. The liver sustains considerable “abuse” from a variety of toxic elements and chemicals, and therefore it needs to be capable of full regeneration. NOTE: Many diseases and exposures can harm it beyond the point of repair. These include cancer, hepatitis, certain medication overdoses, and fatty liver disease.

In the liver, ethanol is met with an enzyme called alcohol dehydrogenase and converts ethanol into acetaldehyde [ass-eh-tal-de-hide]. This chemical is more toxic than ethanol, so the liver uses another enzyme to convert acetaldehyde into acetate, which is non-toxic to the human body. NOTE: the amount of alcohol consumed + the timeframe it is consumed [and a variety of other factors] will influence the ability of the liver to effectively convert acetaldehyde all the way into acetate. The liver can’t handle the entire workload effectively therefore ethanol (before being metabolised) will go straight from the liver to the bloodstream and make its way directly to the heart.

NOTE: Genetics will play a role! Certain people do not produce the liver enzymes in enough quantity to properly breakdown ethanol.

5. Blood leaves the liver through the hepatic veins. The hepatic veins carry blood to the inferior vena cava—the largest vein in the body—to the right side of the heart. The heart will beat and send the incoming blood to the lungs to oxygenate and expel carbon dioxide as we breath out. This is how ethanol can be on your breath. Inside the lungs, at the very end of the bronchioles, are hollow air sacs called alveoli where there is a gas exchange. Ethanol evaporates through capillaries into the air sacs and exhaled out of the body. Breathalysers can detect the quantity of ethanol in a person’s system based on the quantity of ethanol in our breath.

6. Not all the ethanol will expel from the body via the breath. The rest will flow back to the heart, with newly oxygenated blood, and then get pumped all the way up to the brain and around the body. NOTE: Ethanol is water soluble. It will be distributed to every cell in the body except bone and fatty tissue [some will enter fat cells but not easily]. Ethanol will interact with every other cell i.e., every organ, gland, nerve, muscle etc.

7. Ethanol will affect and compromise protein synthesis inside muscle tissue. Therefore, if you have been training at the gym, running, swimming etc., your muscles will not effectively be able to repair.

8. Once ethanol has reached the brain, it will cross the blood-brain barrier and begin to affect chemical messengers [neurotransmitters] in the grey matter of the brain. It affects serotonin, dopamine, gamma-amino-butyric-acid (aka GABA), glutamate, endorphins etc. The person will experience pleasure, euphoria, lowered inhibitions [related to dopamine], lowered cognitive ability (e.g., decision making/problem solving, emotion regulation) and lowered coordination and reflexes.

The more ethanol ingested, the more dopamine is secreted and communicated between neurons (i.e., nerve cells). One of dopamine’s functions is to make you feel pleasure or ‘rewarded’ for doing things that are good for humans, hence, from an evolutionary perspective, we are likely to do them again to help us thrive in our environment and social world. Dopamine is secreted when we:

• eat healthy foods (but also recently developed processed foods that are high in sugar and salt)
• exercise
• achieve goals
• be productive (e.g., finish a task like cleaning, cooking, work-related tasks)
• master new skills (e.g., learning an instrument or a new talent), and
• have positive and stimulating social interactions

Ethanol influences so much dopamine secretion and communication that the brain becomes unable to make responsible decisions cognitively. The simultaneous experience of euphoria and lowered cognitive ability means we are more likely to be “happy” about making irresponsible decisions.

Increased dopamine is how drinking alcohol “blocks” unpleasant emotions like fear, stress, anxiety, and insecurity. When we don’t feel these unpleasant, yet necessary, emotions we will behave in ways that are dangerous, abnormal, potentially embarrassing, and generally problematic.

Another significant brain region affected by ethanol is the hypothalamus and the pituitary glad [together known as the hypothalamic-pituitary axis]. These structures control the entire hormonal system. The hypothalamus monitors the body, and it will send instructions to the pituitary gland based on information it receives from the hypothalamus. The hypothalamus is aware that ethanol is flooding the brain and it starts adjusting the secretion of hormones via the pituitary gland.

One of the instructions it gives the pituitary gland is to start modulating the adrenal glands to secrete cortisol (i.e., stress hormone) and epinephrine and norepinephrine (i.e., adrenaline).

Now, our cognitive capacity is diminished, inhibitions are lowered, and we will experience a rush of stress hormones and adrenaline coursing through the body. Cortisol and adrenaline will provide a boost of energy. It will increase the heart rate, blood pressure, body sweat, sugar levels in the bloodstream, and enhances the brain’s ability to use glucose. Glucose is a “fuel” source for brain functioning, including the generation of neurotransmitters. Behaviourally, we can see this in children when we say they are “hyperactive” because they’ve ingested too much sugar.

The pituitary gland will also slow the secretion of anti-diuretic hormone (aka. vasopressin). A diuretic is something that makes us urinate. If the anti-diuretic hormone (also called vasopressin) slows down, then we won’t be “holding on” to water as effectively, hence we begin to urinate more. People call this “breaking the seal”.

9. South of the body, blood is pumped into the kidneys via the renal artery which spreads through the renal cortex. The blood is then filtered into urine and expelled from the body. The lowered anti-diuretic hormone will dilate (become wider/bigger or more open) blood vessels in the kidneys which means more blood gets passed through and filtered, but it also means we lose a lot more body water which leads to dehydration. Vasopressin is essential in the control of osmotic balance, blood pressure regulations, and kidney function, therefore, when vasopressin is lowered, we are losing essential water and minerals/electrolytes. Electrolytes are involved in urination because the kidneys need them to make the process of filtering blood more efficient.

The loss of water and electrolytes will contribute to a hangover. Electrolytes play a role in cellular water absorption so if we are losing more water than we are bringing in, and we are losing the electrolytes that support the absorption of water, we become dehydrated very quickly.

10. The Hangover

Symptoms: nausea, fatigue, diarrhoea, vomiting, paranoia, anxiety, anorexia (i.e., loss of appetite), increased thirst, muscle weakness, irritability, sweating, increased blood pressure, and headache.

The exact cause of a “hangover” is not yet known however variables affecting the hangover are:

• individual differences such as sex, size, body fat, genetics etc
• lack of sleep
• general health
• drinking behaviour e.g., frequency, duration, quantity
• food intake before and during
• water intake before and after
• your body’s ability to metabolise alcohol i.e., excessive amounts of acetaldehyde due to fewer enzymes to metabolise alcohol in the liver before entering the bloodstream
• general behaviour while drinking e.g., poly-substance use, dancing, sexual activity, risk-taking behaviours etc.

Strategies for Controlled Drinking

• Setting personal drinking limits and sticking to it
• Alternating alcoholic drinks with soft drinks i.e., one alcoholic drink then a water, soft drink, or juice
• Have a meal before drinking
• Switching to low alcohol drinks
• Having regular alcohol-free days/weeks/months
• Identifying high risk situations for heavy drinking and creating a management plan

Engaging in alternative activities to drinking

Addiction fundamentally alters the brain’s reward and decision-making systems through well-documented neurobiological mechanisms. When substances like drugs (including alcohol and nicotine) are consumed, they trigger massive releases of dopamine in the brain’s reward circuit, particularly in areas like the nucleus accumbens and ventral tegmental area. With repeated exposure, the brain adapts by reducing natural dopamine production and decreasing the number of dopamine receptors, creating tolerance and requiring increasingly larger amounts of the substance to achieve the same effect. This neuroadaptation hijacks the brain’s natural reward system, making everyday activities less rewarding while the addictive substance becomes disproportionately important.

Over time, addiction also impairs the prefrontal cortex, the brain region responsible for executive functions like decision-making, impulse control, and weighing long-term consequences. This creates a neurological double-bind: the midbrain structures driving craving and drug-seeking behaviour become hyperactive, while the prefrontal systems that would normally regulate these impulses become weakened. Chronic substance use also disrupts stress response systems, making individuals more vulnerable to relapse during difficult periods. These changes help explain why addiction is recognised as a chronic brain disease rather than simply a matter of willpower – the neuroplastic changes can persist long after substance use stops, though the brain does have remarkable capacity for recovery with sustained abstinence and appropriate treatment.

The Challenge of Stopping

The challenge of stopping stems from the profound neurobiological changes addiction creates in the brain’s fundamental survival systems. The brain essentially learns to treat the addictive substance as necessary for survival, similar to food or water. When someone tries to quit, they face intense physical withdrawal symptoms as their neurochemistry struggles to return to homeostasis, combined with psychological cravings that can persist for months or years. The damaged prefrontal cortex makes it extremely difficult to override these powerful urges with rational decision-making, while stress, environmental cues, and emotional states can trigger automatic drug-seeking responses that feel almost involuntary. This creates a cycle where attempts to quit often lead to temporary success followed by relapse, which many interpret as personal failure rather than recognising it as part of the neurological reality of the condition.

Addiction appears progressive because tolerance drives escalating use over time, while the brain’s reward system becomes increasingly dysregulated. What begins as recreational use gradually shifts to compulsive use as natural dopamine production diminishes and neural pathways become more deeply entrenched. The condition typically follows a predictable pattern: initial experimentation leads to regular use, then to use despite negative consequences, and finally to compulsive use where the person continues despite severe impairment in major life areas. Additionally, chronic substance use often damages the brain regions responsible for insight and self-awareness, making it harder for individuals to recognise the severity of their condition. The progressive nature is also influenced by external factors – as addiction advances, people often lose social supports, employment, and housing, creating additional stressors that fuel continued use and make recovery more challenging.

Understanding addiction when you’re not “addicted” to alcohol or other drugs

The difficulty in understanding addiction, even among people with their own compulsive behaviors, stems from several key differences in how these conditions manifest and are perceived. While behaviors like sugar consumption, social media use, or shopping can indeed activate similar dopamine pathways, they typically don’t create the same level of neurobiological hijacking that occurs with substances like alcohol, opioids, or stimulants. Addictive drugs often produce dopamine surges 2-10 times greater than natural rewards, creating more profound and lasting changes to brain structure and function. Additionally, many behavioral compulsions allow people to maintain relatively normal functioning in major life areas, whereas substance addiction typically leads to progressive deterioration across multiple domains – relationships, work, health, and legal standing.

The social and cognitive factors also create barriers to understanding. Most people can relate to losing control occasionally – eating too much dessert or spending too much time scrolling their phone – but these experiences usually involve temporary lapses that can be corrected relatively easily through willpower or environmental changes. This creates a false sense of equivalency where people think “I can stop eating cookies when I want to, so why can’t they just stop drinking?” They don’t grasp that addiction involves a qualitatively different level of brain change where the substance has become neurobiologically essential, not just psychologically preferred. There’s also often a moral lens applied to addiction that doesn’t exist for other compulsive behaviours – society tends to view overconsumption of legal, socially acceptable things as personal quirks or minor character flaws, while addiction to illegal substances or excessive alcohol use carries heavy stigma and assumptions about moral failing, making it harder to see as a medical condition requiring treatment rather than simply better self-control.

A Word On Nicotine (Tobacco Products)

Yes, nicotine absolutely does release large amounts of dopamine, making it highly addictive despite being legal and socially accepted in many contexts. Nicotine causes an increase in dopamine levels in the brain’s reward pathways, creating feelings of satisfaction and pleasure.Research shows that nicotine, like opioids and cocaine, can cause dopamine to flood the reward pathway up to 10 times more than natural rewards.

This helps explain why nicotine addiction can be so powerful and difficult to overcome, even though people often view smoking or vaping as less serious than other forms of substance addiction. Repeated activation of dopamine neurons in the ventral tegmental area by nicotine leads not only to reinforcement but also to craving and lack of self-control over intake. The addiction develops through the same basic mechanisms as other substances – as people continue to smoke, the number of nicotine receptors in the brain increases, requiring more of the substance to achieve the same dopamine response.

What makes nicotine particularly insidious is its legal status and social acceptance, which can make people underestimate its addictive potential. The rapid delivery of nicotine to the brain (within 10-20 seconds when smoked) creates an almost immediate reward that strongly reinforces the behaviour. This is why many people who successfully quit other substances still struggle with nicotine, and why nicotine addiction often serves as a gateway that primes the brain’s reward system for addiction to other substances.