Alcohol and other drugs play a significant role in the onset and course of neurological disorders.

As toxic agents, these substances directly affect nerve cells and muscles, and therefore have an impact on the structure and  functioning of both the central and peripheral nervous systems. For example, long-term use of ethanol is associated with damage to brain structures which are responsible for cognitive abilities (e.g. memory, problem-solving) and emotional functioning.

In people with a history of chronic alcohol consumption the following abnormalities have been observed: cerebral atrophy or a reduction in the size of the cerebral cortex, reduced supply of blood to this section of the brain which is responsible for higher functions, and disruptions in the functioning of neurotransmitters or chemical messengers. These changes may account for deficits in higher cortical functioning and other abnormalities which are often symptoms of alcohol-related neurological disorders.

The role of alcohol in fetal alcohol syndrome has been known for many years: the condition affects some children born to women who drank heavily during pregnancy. The symptoms of fetal alcohol syndrome include facial abnormalities, neurological and cognitive impairments, and defi cient growth with a wide variation in the clinical features. Not much is known about the prevalence in most countries but, in the United States, available data show that the prevalence is between 0.5 and 2 cases per 1000 births.

According to WHO, though there is little doubt about the role of alcohol in this condition, it is not clear at what level of drinking and during what stage of pregnancy it is most likely to occur. Hence the best advice to pregnant women or those contemplating pregnancy seems to be to abstain from drinking, because without alcohol the disorder will not occur.