The impact on the central nervous system
The reason ethanol is widely used as a legal drug is due to its ability to depress the central nervous system (CNS) (as shown in the table “Alcohol Effects on the Nervous System”). Once ingested, ethanol (not acetaldehyde) easily passes through the blood-brain barrier, allowing it to affect multiple areas of the CNS in a dose-dependent manner. The greater the dose, the stronger the effect (Reilly, 2002). Acute and moderate ethanol consumption leads to changes in cortical excitability and the way signals are transmitted in the CNS, which cause many of the cognitive problems associated with being drunk (Kähkönen, 2005; Volkow et al., 2008). Additionally, increased activity in the limbic region due to dopamine and serotonin actions strengthens the pleasure associated with ethanol consumption, making it highly addictive (Volkow et al., 2008).
Chronic, excessive alcohol consumption can cause permanent harm to the brain, including memory loss, learning difficulties, psychosis, mental confusion, and even paralysis. Although quitting alcohol and taking thiamine supplements may improve some of the damage, some of it may not be reversible (Thomsom, Heap, & Shaw, 1994; Ridley, Draper, & Withall, 2013).
Alcohol Effects on the Nervous System
| Blood Alcohol Level (mg/100ml blood) | Blood Alcohol Content (BAC %) | Effects |
|---|---|---|
| 30 | 0.03 | Improved feeling of happiness, slowed response time to simple stimuli, decreased dexterity and coordination, and heightened likelihood of incidents or mishaps. |
| 60 | 0.06 | Reduced inhibitions, diminished decision-making ability, and growing euphoria. |
| 90 | 0.09 | Loss of social inhibitions, impaired coordination, and noticeable drunkenness. |
| 120 | 0.12 | Clumsiness becomes apparent, physical control is lost, extreme responses tend to occur, and drunkenness is definitely observed. |
| 150 | 0.15 | Unpredictable actions, difficulty speaking clearly, unsteady walking, aggression, and extreme joyfulness. |
| 180 | 0.18 | Loss of ability to control actions and decreased visual function. |
| 400 | 0.400 | Complete loss of consciousness, profound drowsiness, and deep unconsciousness. |
| 500 | 0.500 | Possibility of fatal outcome |
| 600 | 0.600 | Death is inevitable. |
