When structural impairments are not observable or do not exist, neurological impairments are assessed. In the context of FASD, neurological impairments are caused by prenatal alcohol exposure which causes general neurological damage to the central nervous system (CNS), the peripheral nervous system, or the autonomic nervous system. A determination of a neurological problem must be made by a trained physician, and must not be due to a postnatal insult, such as a high fever, concussion, traumatic brain injury, etc.

All four diagnostic systems show virtual agreement on their criteria for CNS damage at the neurological level, and evidence of a CNS neurological impairment due to prenatal alcohol exposure will result in a diagnosis of FAS or pFAS, and functional impairments are highly likely.

Neurological problems are expressed as either hard signs, or diagnosable disorders, such as epilepsy or other seizure disorders, or soft signs. Soft signs are broader, nonspecific neurological impairments, or symptoms, such as impaired fine motor skills, neurosensory hearing loss, poor gait, clumsiness, poor eye-hand coordination. Many soft signs have norm-referenced criteria, while others are determined through clinical judgment. "Clinical judgment" is only as good as the clinician, and soft signs should be assessed by either a pediatric neurologist, a pediatric neuropsychologist, or both.

Other conditions may commonly co-occur with FAS, stemming from prenatal alcohol exposure. However, these conditions are considered alcohol-related birth defects and not diagnostic criteria for FAS.

- Heart: A heart murmur that frequently disappears by one year of age. Ventricular septal defect most commonly seen, followed by an atrial septal defect.

- Bones: Joint anomalies including abnormal position and function, altered palmar crease patterns, small distal phalanges, and small fifth fingernails.

- Kidneys: Horseshoe, aplastic, dysplastic, or hypoplastic kidneys.

- Eyes: Strabismus, optic nerve hypoplasia (which may cause light sensitivity, decreased visual acuity, or involuntary eye movements).

- Occasional problems: ptosis of the eyelid, microophthalmia, cleft lip with or without a cleft palate, webbed neck, short neck, tetralogy of Fallot, coarctation of the aorta, spina bifida, and hydrocephalus.

Neurodevelopmental disorders are impairments of the growth and development of the brain or central nervous system. A narrower use of the term refers to a disorder of brain function that affects emotion, learning ability, self-control and memory and that unfolds as an individual develops and grows.

The term is sometimes erroneously used as an exclusive synonym for autism spectrum disorders.

Neurodevelopmental disorder is a mental disorder. A narrower use of the term refers to a disorder of brain function which affects emotion, learning ability, self-control and memory and which unfolds as the individual grows.

Symptoms of OBS vary with the disease that is responsible. However, the more common symptoms of OBS are confusion; impairment of memory, judgment, and intellectual function; and agitation. Often these symptoms are attributed to psychiatric illness, which causes a difficulty in diagnosis.

Alcohol-related dementia presents as a global deterioration in intellectual function with memory not being specifically affected, but it may occur with other forms of dementia, resulting in a wide range of symptoms. Certain individuals with alcohol-related dementia present with damage to the frontal lobes of their brain causing disinhibition, loss of planning and executive functions, and a disregard for the consequences of their behavior. Other types of alcohol-related dementia such as Korsakoff's Syndrome cause the destruction of certain areas of the brain, where changes in memory, primarily a loss of short term memory, are the main symptom. Most presentations of alcohol dementia are somewhere along the spectrum between a global dementia and Korsakoff's psychosis, and may include symptoms of both.

Individuals affected by alcohol-related dementia may develop memory problems, language impairment, and an inability to perform complex motor tasks such as getting dressed. Heavy alcohol abuse also damages the nerves in arms and legs, i.e. peripheral neuropathy, as well as the cerebellum that controls coordination thereby leading to the development of cerebellar ataxia. These patients frequently have problems with sensation in their extremities and may demonstrate unsteadiness on their feet.

Alcohol-related dementia can produce a variety of psychiatric problems including psychosis (disconnection from reality), depression, anxiety, and personality changes. Patients with alcoholic dementia often develop apathy, related to frontal lobe damage, that may mimic depression. People with alcoholism are more likely to become depressed than people without alcoholism, and it may be difficult to differentiate between depression and alcohol dementia.

Alcohol-related brain damage is the damage that occurs to brain structures or function of the central nervous system as a result of the direct neurotoxic effects of alcohol intoxication or acute withdrawal. The frontal lobes are the most damaged region of the brains of alcohol abusers but other regions of the brain are also affected. The damage that occurs from heavy drinking/high blood alcohol levels causes impairments in judgement and decision making and social skills. These brain changes are linked to poor behavioural control and impulsivity, which tend to worsen the existing addiction problem.

The problems of alcoholism are well known, such as memory disorders, liver disease, high blood pressure, muscle weakness, heart problems, anaemia, low immune function, disorders of the digestive system and pancreatic problems as well as depression, unemployment and family problems including child abuse. Recently attention has been increasingly focused on binge drinking by adolescents and young adults due to neurochemical changes and brain damage which, unlike with alcoholism, can occur after a relatively short period of time; the damage is particularly evident in the corticolimbic region. This brain damage increases the risk of abnormalities in mood and cognitive abilities, increases the risk of dementia and additionally binge drinkers have an increased risk of developing chronic alcoholism.

Individuals who are impulsive are at high risk of addiction due to impaired behavioural control and increased sensation seeking behaviour. Alcohol abuse, especially during adolescence, causes a deterioration of executive functions in the frontal lobe. This brain damage from alcohol actually increases impulsivity and therefore worsens the addictive disorder.

There are five main stages of alcoholism. The first stage,occasional abuse and binge drinking, in this stage one may want to just experiment with alcohol and test their limits. These drinkers may be new to different forms of alcohol. This experimental stage is commonly seen in teens and young adults. These experimental drinkers also frequently engage in binge drinking. While they may not drink regularly, they consume exceptionally enormous amounts of alcohol at one time.

The second stage, increased drinking, in this stage one will leave the experimental stage and start drinking on a regular basis. Instead of just drinking at parties occasionally, one may find themselves drinking every weekend. Increased alcohol consumption can also lead to drinking for these reasons: as an excuse to get together with friends, to alleviate stress, out of boredom, or to combat sadness or loneliness.

The third stage, problem drinking, one will drink to get rid of their problems for them at any moment. As increased drinking continues, one becomes more dependent on alcohol and are at risk of developing alcoholism.

The fourth stage, alcohol dependence, this forms after the problem drinking stage. At this point, one has an attachment to alcohol that has taken over their regular routine. They are aware of the adverse effects, but no longer have control over their alcohol consumption. Alcohol dependence also means that one has developed a tolerance to drinking. As a result, they may have to consume larger quantities to get “buzzed” or drunk.

The fifth stage, addiction and alcoholism, this is the final and most harmful stage. One is addicted and dependent and must have alcohol all the time, if not they have withdrawals. Alcohol withdrawal is the changes the body goes through when a person suddenly stops drinking after prolonged alcohol abuse, or if one does not have alcohol for a period of time. Symptoms include trembling (shakes), insomnia, anxiety, and other physical and mental symptoms. If the alcohol is withdrawn suddenly, the brain is like an accelerated vehicle that has lost its brakes. Not surprisingly, most symptoms of withdrawal are symptoms that occur when the brain is overstimulated (Drugs.com). People with alcohol addiction physically crave the substance and are often inconsolable until they start drinking again. With prolonged abstinence neurogenesis occurs which can potentially reverse the damage from alcohol abuse.

While researchers have found that moderate alcohol consumption in older adults is associated with better cognition and well-being than abstinence, excessive alcohol consumption is associated with widespread and significant brain lesions. The effects can manifest much later—mid-life Alcohol Use Disorder has been found to correlate with increased risk of severe cognitive and memory deficits in later life. Alcohol related brain damage is not only due to the direct toxic effects of alcohol; alcohol withdrawal, nutritional deficiency, electrolyte disturbances, and liver damage are also believed to contribute to alcohol-related brain damage.

Treatment of OBS varies with the causative disorder or disease. It is important to note that it is not a primary diagnosis and a cause needs to be sought out and treated.

Alcohol-related dementia is a broad term currently preferred among medical professionals. Many experts use the terms alcohol (or alcoholic) dementia to describe a specific form of ARD, characterized by impaired executive function (planning, thinking, and judgment). Another form of ARD is known as wet brain (Wernicke-Korsakoff syndrome), characterized by short term memory loss and thiamine (vitamin B1) deficiency. ARD patients often have symptoms of both forms, i.e. impaired ability to plan, apathy, and memory loss. ARD may occur with other forms of dementia (mixed dementia). The diagnosis of ARD is widely recognized but rarely applied, due to a lack of specific diagnostic criteria.

On many non-medical websites, the terms wet brain and alcohol-related dementia are often used interchangeably, creating significant confusion. Additionally, the term alcohol-induced persistent dementia is another non-specific name that is sometimes used.

Alcohol dependence is a previous psychiatric diagnosis in which an individual is physically or psychologically dependent upon alcohol (also known formally as ethanol). In 2013 it was reclassified as alcohol use disorder (alcoholism) along with alcohol abuse in DSM-5.

From the ICD-9 database:

- A chronic disease in which a person craves drinks that contain alcohol and is unable to control his or her drinking. A person with this disease also needs to drink greater amounts to get the same effect and has withdrawal symptoms after stopping alcohol use. Alcoholism affects physical and mental health, and can cause problems with family, friends, and work.

- A disorder characterized by a pathological pattern of alcohol use that causes a serious impairment in social or occupational functioning.

- A primary, chronic disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. The disease is often progressive and fatal. It is characterized by impaired control over drinking, preoccupation with the drug alcohol, use of alcohol despite adverse consequences, and distortions in thinking, most notably denial. Each of these symptoms may be continuous or periodic. (morse & flavin for the joint commission of the national council on alcoholism and drug dependence and the american society of addiction medicine to study the definition and criteria for the diagnosis of alcoholism: in jama 1992;268:1012-4)

- For most adults, moderate alcohol use is probably not harmful. However, about 18 million adult Americans are alcoholics or have alcohol problems. Alcoholism is a disease with four main features:

- craving - a strong need to drink

- loss of control - not being able to stop drinking once you've started

- physical dependence - withdrawal symptoms, such as nausea, sweating, or shakiness when you don't drink

- tolerance - the need to drink greater amounts of alcohol to feel the same effect

- Temporary mental disturbance marked by muscle incoordination and paresis as the result of excessive alcohol ingestion.

Developmental disorders comprise a group of psychiatric conditions originating in childhood that involve serious impairment in different areas. There are several ways of using this term. The most narrow concept is used in the category "Specific Disorders of Psychological Development" in the ICD-10. These disorders comprise language disorders, learning disorders, motor disorders and autism spectrum disorders. In broader definitions ADHD is included, and the term used is neurodevelopmental disorders. Yet others include antisocial behavior and schizophrenia that begins in childhood and continues through life. However, these two latter conditions are not as stable as the other developmental disorders, and there is not the same evidence of a shared genetic liability.

Developmental disorders are present from early life. They usually improve as the child grows older, but they also entail impairments that continue through adult life. There is a strong genetic component, and more males are afflicted than females.

The term "multisystem developmental disorder" has also been used to describe various developmental disorders. These include:

- Alagille syndrome, an autosomal dominant disorder with a wide range of features and manifestations. Its five most significant features are chronic cholestasis, a condition where bile cannot flow from the liver to the duodenum, occurring in 95% of cases; heart abnormalities (over 90%); butterfly vertebrae; posterior embryotoxon and a distinctive face (prominent forehead, deep-set eyes, and a pointed chin).

- Rubinstein-Taybi syndrome, a mental retardation syndrome characterized by broad thumbs, facial abnormalities, and big toes alongside mental retardation.

- Williams syndrome, a neurodevelopmental disorder characterized by a unique profile of strengths and deficits; most with the condition have mild mental retardation but have grammatical and lexical abilities above what would be expected from their IQs. They are hypersocial and empathetic, but social isolation is commonly experienced.

- Proteus syndrome, a congenital disorder causing disproportionate growth of skin, bone, and other tissues.

- Asphyxiating thoracic dysplasia, a autosomal recessive skeletal disorder with an estimated prevalence of between 1 in 100,000 and 1 in 130,000 live births.

Neonatal encephalopathy (NE), also known as neonatal hypoxic-ischemic encephalopathy (neonatal HIE or NHIE), is defined by signs and symptoms of abnormal neurological function in the first few days of life in an infant born at term. In this condition there is difficulty initiating and maintaining respirations, a subnormal level of consciousness, and associated depression of tone, reflexes, and possibly seizures. Encephalopathy is a nonspecific response of the brain to injury which may occur via multiple methods, but is commonly caused by birth asphyxia.

Depending on the location of the brain lesion different symptoms are more frequent:

- Brainstem tegmentum. - Ocular: pupillary changes. Extraocular muscle palsy; gaze palsy: nystagmus.

- Hypothalamus. Medulla: dorsal nuc. of vagus. - Autonomic dysfunct.: temperature; cardiocirculatory; respiratory.

- Medulla: vestibular region. Cerebellum. - Ataxia.

- Dorsomedial nuc. of thalamus. Mammillary bodies. - Amnestic syndrome for recent memory.

Mamillary lesion are characteristic-small petechial hemorrhages are found.

- Diffuse cerebral dysfunction.- Altered cognition: global confusional state.

- Brainstem: periaqueductal gray.- Reduction of consciousness

- Hypothalamic lesions may also affect the immune system, which is known in alcohol abusers, causing dysplasias and infections.

In neonates born at or beyond 35 weeks, neonatal encephalopathy may present itself as the following symptoms:

- Reduced level of consciousness

- Seizures (which peak at 48 hours)

- Difficulty initiating and maintaining respiration

- Depression of tone and reflexes

Learning disabilities are diagnosed when the children are young and just beginning school. Most learning disabilities are found under the age of 9.

Young children with communication disorders may not speak at all, or may have a limited vocabulary for their age. Some children with communication disorders have difficulty understanding simple directions or are unable to name objects. Most children with communication disorders are able to speak by the time they enter school, however, they continue to have problems with communication. School-aged children often have problems understanding and formulating words. Teens may have more difficulty with understanding or expressing abstract ideas.

Alcohol abuse among pregnant women causes their baby to develop fetal alcohol syndrome. Fetal alcohol syndrome is the pattern of physical abnormalities and the impairment of mental development which is seen with increasing frequency among children with alcoholic mothers. Alcohol exposure in a developing fetus can result in slowed development of the fetal brain, resulting in severe retardation or death. Surviving infants may suffer severe abnormalities such as abnormal eyes, fissures, lips and incomplete cerebella. Some infants may develop lung disease. It is even possible that the baby throughout pregnancy will develop heart defects such as ventricular septal defect or atrial septal defect. Experts suggest that pregnant women take no more than one unit of alcohol per day. However, other organizations advise complete abstinence from alcohol while pregnant.

Individuals with an alcohol use disorder will often complain of difficulty with interpersonal relationships, problems at work or school, and legal problems. Additionally, people may complain of irritability and insomnia. Alcohol abuse is also an important cause of chronic fatigue.

Signs of alcohol abuse are related to alcohol's effects on organ systems. However, while these findings are often present, they are not necessary to make a diagnosis of alcohol abuse. Signs of alcohol abuse show its drastic effects on the central nervous system, including inebriation and poor judgment; chronic anxiety, irritability, and insomnia. Alcohol's effects on the liver include elevated liver function tests (classically AST is at least twice as high as ALT). Prolonged use leads to cirrhosis and liver failure. With cirrhosis, patients develop an inability to process hormones and toxins. The skin of a patient with alcoholic cirrhosis can feature cherry angiomas, palmar erythema and — in acute liver failure — jaundice and ascites. The derangements of the endocrine system lead to the enlargement of the male breasts. The inability to process toxins leads to liver disease, such as hepatic encephalopathy.

Alcohol abuse can result in brain damage which causes impairments in executive functioning such as impairments to working memory, visuospatial skills, and can cause an abnormal personality as well as affective disorders to develop. Binge drinking is associated with individuals reporting fair to poor health compared to non-binge drinking individuals and which may progressively worsen over time. Alcohol also causes impairment in a person's critical thinking. A person's ability to reason in stressful situations is compromised, and they seem very inattentive to what is going on around them. Social skills are significantly impaired in people suffering from alcoholism due to the neurotoxic effects of alcohol on the brain, especially the prefrontal cortex area of the brain. The social skills that are impaired by alcohol abuse include impairments in perceiving facial emotions, difficulty with perceiving vocal emotions and theory of mind deficits; the ability to understand humour is also impaired in alcohol abusers. Adolescent binge drinkers are most sensitive to damaging neurocognitive functions especially executive functions and memory. People who abuse alcohol are less likely to survive critical illness with a higher risk for having sepsis and were more likely to die during hospitalization.

The classic triad of symptoms found in Wernicke's encephalopathy is:

- ophthalmoplegia (later expanded to other eye movement abnormalities, most commonly affecting the lateral rectus or any eye sign. Lateral nystagmus is most commonly seen although lateral rectus palsy, usually bilateral, may be seen).

- ataxia (later expanded to imbalance or any cerebellar signs)

- confusion (later expanded to other mental changes. Has 82% incidence in diagnosis cases)

However, in actuality, only a small percentage of patients experience all three symptoms, and the full triad occurs more frequently among those who have overused alcohol.

Also a much more diverse range of symptoms has been found in patients with this condition, including:

- pupillary changes, retinal hemorrhage, papilledema, impaired vision and hearing, vision loss

- hearing loss,

- fatigability, apathy, irritability, drowsiness, psycho and/or motor slowing

- dysphagia, blush, sleep apnea, epilepsy and stupor

- lactic acidosis

- memory impairment, amnesia, depression, psychosis

- hypothermia, polyneuropathy, hyperhidrosis.

Although hypothermia is usually diagnosed with a body temperature of 35 °C / 95° Fahrenheit, or less, incipient cooling caused by deregulation in the CNS needs to be monitored because it can promote the development of an infection. The patient may report feeling cold, followed by mild chills, cold skin, moderate pallor, tachycardia, hypertension, tremor or piloerection. External warming techniques are advised to prevent hypothermia.

Among the frequently altered functions are the cardio circulatory. There may be tachycardia, dyspnea, chest pain, orthostatic hypotension, changes in heart rate and blood pressure. The lack of thiamine sometimes affects other major energy consumers, the myocardium, and also patients may have developed cardiomegaly. Heart failure with lactic acidosis syndrome has been observed. Cardiac abnormalities are an aspect of the WE, which was not included in the traditional approach, and are not classified as a separate disease.

Infections have been pointed out as one of the most frequent triggers of death in WE. Furthermore, infections are usually present in pediatric cases.

In the last stage others symptoms may occur: hyperthermia, increased muscle tone, spastic paralysis, choreic dyskinesias and coma.

Because of the frequent involvement of heart, eyes and peripheral nervous system, several authors prefer to call it Wernicke disease rather than simply encephalopathy.

Early symptoms are nonspecific, and it has been stated that WE may present nonspecific findings. In Wernicke Korsakoff’s syndrome some single symptoms are present in about one-third.

Alcohol is a liquid form substance which contains ethyl alcohol (also known formally as ethanol) that can cause harm and even damage to a persons DNA. "Alcohol consumption is recognized worldwide as a leading risk factor for disease, disability, and death." and is rated as the most used and abused substance by adolescences. Adolescence is a transitional stage of physical and psychological changes, usually a time in a person life in which they go through puberty. Combining these transitional stages and the intake of alcohol, can leave a number of consequences for an adolescent.

A drug-related blackout is a phenomenon caused by the intake of any substance or medication in which short term and long term memory creation is impaired, therefore causing a complete inability to recall the past. Blackouts are most frequently associated with GABAergic drugs. Blackouts are frequently described as having effects similar to that of anterograde amnesia, in which the subject cannot recall any events after the event that caused amnesia. Research on alcohol blackouts was begun by E. M. Jellinek in the 1940s. Using data from a survey of Alcoholics Anonymous (AA) members, he came to believe that blackouts would be a good determinant of alcoholism. However, there are conflicting views whether this is true. The negative psychological effects of an alcohol-related blackout are often worsened by those who suffer from anxiety disorders. Impairment of the liver will also allow more alcohol to reach the brain and hasten the individual's blackout.

The term "blackout" can also refer to a complete loss of consciousness, or syncope.

Multisystem developmental disorder (MSDD) is a term used by Stanley Greenspan to describe children under age 3 who exhibit signs of impaired communication as in autism, but with strong emotional attachments atypical of autism. It is described in the DC:0-3R manual as an optional diagnosis for children under two years of age.

Alcohol in pregnancy is the use of alcohol (also known formally as ethanol) during gestation. This also includes the time period between conception and awareness of the pregnancy. Alcohol use not only can result in Fetal Alcohol Spectrum Disorder (FASD), but it can result in one or many other disorders and conditions. Not all women who consume alcohol during pregnancy will have a baby with all of the features and characteristics of FASP. Alcohol use during pregnancy also can cause spontaneous abortion, stillbirth, low birthweight, and prematurity. Not all infants exposed to alcohol in utero will have defects related to the alcohol consumption. Alcohol use during pregnancy can also result in the inability to care for an infant after the birth if the drinking continues. The use of alcohol during pregnancy is associated with domestic violence and potential harm to the infant.