There are five main neurological disorders attributable to alcohol abuse. They are:

Alcohol Intoxication

The acute neurological effects of alcohol begin with excitement and end with stupor or coma. The behavioural and emotional effects occurring in the early stages of intoxication include exhilaration, loss of restraint and decreased self awareness.

If rapid consumption continues, a number of cognitive and psychomotor impairments can be detected. There is a decreased sensitivity in fine discrimination, judgement is impaired, and concentration and memory are adversely affected.

Acute Alcohol-Induced Memory Loss (Blackouts)

'Blackouts' can be fragmentary - the person is unaware of the memory loss - or may be a fugue-like state where a person finds themselves in a situation with no idea of how they got there. 'Blackouts' are usually associated with severity of alcohol dependence and rapid increase of blood alcohol concentration.

Idiosyncratic (Pathological) Intoxication

Idiosyncratic intoxication induces behaviour that is out of proportion to both the amount of alcohol consumed and the setting in which it occurs. Evidence suggests that this occurs in people with pre-existing brain impairment and is supported by the knowledge that this group are unduly prone to intoxication.

Tolerance, Neuroadaptation and Alcohol Dependence Syndrome

Prolonged frequent and excessive drinking leads to a person appearing relatively unaffected at blood alcohol concentrations that would be intoxicating for a social drinker. The brain increasingly adapts to the presence of large amounts of alcohol and the individual becomes dependent on alcohol to maintain neurobehavioural and emotional stability.

Alcohol Withdrawal Syndrome (Tremor, Hallucinosis, Seizures, Delirium Tremens)

The nature and severity of the symptoms appearing during withdrawal are determined largely by the quantity and frequency of recent drinking. However, it is also influenced by the presence of serious physical illness, for example, cirrhosis, malnutrition or pancreatitis.
The withdrawal syndrome may be severe and protracted and medical consultation might be required.
There are distinct symptoms that most commonly occur during a reduction in blood alcohol level:

• Tremors (3-12 hours)
• Hallucinosis (3-12 hours)
• Seizures (12-48 hours)
• Delirium tremens (3-4 days)

The intensity of the withdrawal syndrome is related to the blood alcohol levels maintained prior to cessation.