Neurological Effects of Alcohol

Alcohol, Seizures and Epilepsy

Epilepsy is a brain disorder in which unprovoked (or provoked, for example, by alcohol) seizures occur at random times. Alcohol-related seizures usually present as generalized muscle cramps with shaking or uncontrollable moves that last from several seconds to few minutes ^[1].

What increases the risk of alcohol-related seizures?

Binge drinking, in combination with staying out a lot at night and skipped meals, may increase the risk of seizures in both healthy persons and individuals with epilepsy (2321).

Long term heavy drinking may increase the risk of seizures ^[2]. It is not alcohol alone that triggers seizures; disturbed electrolyte balance after drinking large amounts of liquid, mineral deficiencies, trauma, missed medications and alcohol withdrawal may trigger seizures as well ^[2].

Seizures as a part of withdrawal syndrome may occur 6-48 hours after stopping chronic heavy drinking ^[1]; they may be prevented and treated with diazepam ^[3].

Children with fetal alcohol spectrum disorder (FASD) are at increased risk to develop epilepsy ^[4].

Small amounts of alcohol (1-2 drinks per day) does not seem to increase the risk of seizures in epileptics ^[9]. There is not enough evidence to recommend complete abstinence to individuals with well-controlled epilepsy ^[5]. Amount of alcohol that may trigger seizures differ from person to person, so every epileptic should decide to drink or not.

Alcohol and Antiepileptic Medications

Antiepileptic medications may increase the depressant effect of alcohol.

Alcohol may increase the side effects of antiepileptic medications, for example, alcohol may aggravate dizziness and headache caused by carbamazepine, or drowsiness caused by diazepam or phenobarbital ^[6,7]. Alcohol drunk at a single occasion may increase phenytoin effects and daily alcohol drinking may decrease them ^[8]. An epileptic person should not skip medications when drinking, since skipping medications may be much more dangerous than eventual alcohol-medication interactions ^[10].

Alcohol and Multiple Sclerosis (MS)

According to one 2012 study, there is no association between alcohol consumption and the risk of multiple sclerosis ^[11].

In one 2011 study, researchers have found an association (not necessary a cause-effect relation) between light or moderate alcohol consumption and a slower course of “relapsing multiple sclerosis,” but not ” primary progressive multiple sclerosis” ^[12]. There could be life-style or diet factors other than alcohol in moderate drinkers that actually caused a slower progression of MS, so this study have not confirmed that alcohol itself affects MS ^[12].

Alcoholic Neuropathy

Alcoholic neuropathy is a nerve damage caused by direct ethanol toxicity and vitamin B1 (thiamin) deficiency.

Symptoms include slowly progressing (over months) numbness, tingling (pins and needles), burning or pain, starting in soles and progressing to feet and toes, followed by feet weakness, (“painful legs and moving toes”) and, in severe cases, the same symptoms in fingertips and hands (giving the so-called “stocking and glove” pattern) ^[13,14,15]. Treatment may include alcohol abstinence, physical rehabilitation, medications to decrease unpleasant sensations, and vitamins B ^[16]. The condition may improve after stopping drinking ^[17].

Nutritional optic neuropathy, a damage of the optic nerve with reduction of color vision and visual field defects may be caused by lack of certain vitamins or other nutrients in a chronic alcoholic on a poor diet ^[19]. Treatment may include stopping drinking alcohol and eventual smoking, vitamin B complex and other nutrients ^[20]. Except in advances cases, complete recovery may be expected ^[21].

Chronic excessive drinking can result in brain shrinkage (atrophy) and alcoholic dementia, which may improve after stopping drinking ^[13,18]. Brain shrinkage can be detected by computer tomography (CT) or magnetic resonance (MRI) ^[13].

Drinking and Memory

Short-Term Effects of Alcohol On Memory

According to one 1981 study, the amount of alcohol that results in blood alcohol concentration up to 0.1 g/100 mL (for example, up to four drinks in 1 hour by a 160 lbs person) may improve memory for the events that occurred before drinking ^[22].

When drinking, a person may store information into a long-term memory less efficiently than when not drinking ^[23]. Short-term memory (minutes) or the ability to recall events stored in the long-term memory before drinking are less affected by a single drinking session ^[23].

Drinking that results in a quick raise of blood alcohol concentration above 0.15 g/100 mL (for example, seven drinks in one hour on an empty stomach by a 160 lbs person) may, in some people, causes blackouts – partial or complete loss of memory for the events that occurred after starting drinking (anterograde amnesia) ^[23]. Blackouts may last from few minutes to few days. Blackout does not mean passing out; during a blackout, a person may drive a car or perform other complicated tasks and except of being intoxicated, may appear “normal” to others.

During the blackout, a person can recall events that occurred in the recent few minutes and those before the blackout, but not the events that occurred more than few minutes ago. After the blackout, when sober, a person experiences partial or complete loss of memory for the events that occurred during blackout.

Blackouts may occur in both social and heavy chronic drinkers; vulnerability to blackouts may vary greatly from person to person ^[23]. Combining alcohol with drugs, such as benzodiazepines or marijuana may increase the risk of blackouts ^[23].

Long-Term Effects of Alcohol On Memory

Long-term moderate drinking may reduce the decline of the cognitive functions in old people ^[18,24].

• Heavy drinking impairs the day-to-day memory ^[25].
• Chronic heavy drinking may result in an irreversible loss of the short-term memory (seconds, minutes) and long-term memory (years) and ability to learn new things (Korsakoff psychosis) what often results in making stories (confabulation) to cover the lack of actual memory ^[26]. Korsakoff psychosis is caused by vitamin B1 (thiamin) deficiency ^[26].