Mercury Poisoning

Autism

Extreme shyness, social withdrawal, feeling overly sensitive, introversion

Social deficits, social withdrawal, self reports of extreme shyness, aloofness

Mood swings; flat affect; mask face; laughing or crying without provocation; episodes of hysteria

Mood swings; flat affect in some; no facial expression; laughing or crying without reason

Anxiety; nervousness; tremulousness; somatization of anxious feelings

Anxiety, nervousness; anxiety disorder

Schizoid tendencies, neurosis, obsessive-compulsive traits, repetitive dreams

Schizophrenic traits; OCD traits; repetitive behaviors and thoughts

Lack of eye contact; being less talkative; hesitancy to engage others

Lack of eye contact, gaze avoidance; avoids conversation

Depression, lack of interest in life, lassitude, fatigue, apathy; feelings of hopelessness; melancholy

Association with depression; lack of initiative, diminished outward emotions

On the one hand, less overtly active, unwilling to go outside or be with others; on the other hand, increased restlessness

Tendency to withdraw, especially to own rooms, prefer to be alone; hyperactivity

Irrational fears

Irrational fears

Irritability, anger, and aggression; in children this may manifest as frequent and severe temper tantrums

Irritability and aggression; severe temper tantrums in children

Psychotic episodes; hallucinations, hearing voices; paranoid thoughts

Psychotic talk, paranoid thoughts

Impaired face recognition

Impaired face recognition

Mercury Poisoning

Autism

Complete loss of speech in adults or children; failure to develop speech in infants

Delayed language onset; failure to develop speech

Dysarthria; speech difficulties from intention tremor; slow and slurred speech

Dysarthria; dyspraxia and oral-motor planning difficulties; unintelligible speech

Aphasia, the inability to use or understand words, inability to comprehend speech although ability to hear sound is intact

Speech comprehension deficits, although ability to hear sound is intact

Difficulties verbalizing; word retrieval problems

Echolalia; pronoun reversals, word meaning and pragmatic errors; limited speech production

Auditory disturbance; difficulties differentiating voices in a crowd

Difficulties following conversational speech with background noise

Sound sensitivity

Sound sensitivity

Hearing loss; deafness in very high doses

Mild to profound hearing loss

Poor performance on standardized language tests

Poor performance on verbal IQ tests

Mercury Poisoning

Autism

Abnormal sensation or numbness around mouth and extremities (paresthesia); burning feet

Abnormal sensation in mouth and extremities; excessive mouthing of objects (infants); toe walking; difficulty grasping objects

Sound sensitivity

Sound sensitivity

Excessive pain when bumping; abnormal touch sensations; touch aversion

Insensitivity or overreaction to pain and touch; touch aversion; stiff to hold

Loss of position in space

Vestibular system abnormalities; difficulty orienting self in space

Normal pinprick tests

Normal pinprick tests

Mercury Poisoning

Autism

Involuntary jerking movements, e.g., arm flapping, ankle jerks, myoclonal jerks; choreiform movements; circling (cats); rocking; purposeless movement of extremities; twitching, shaking; muscular spasticity

Stereotyped movements such as arm flapping, jumping, circling, spinning, rocking; myoclonal jerks; choreiform movements

Unsteadiness in handwriting or an inability to hold a pen; deficits in eye-hand coordination; limb apraxia; intention tremors; loss of fine motor skills

Difficulty in writing with or holding a pen; poor eye-hand coordination; limb apraxia; problems carrying out intentional movements (praxia)

Ataxia: gait impairment; severity ranging from mild incoordination, clumsiness to complete inability to walk, stand, or sit; staggering, stumbling; loss of motor control

Abnormal gait and posture, clumsiness and incoordination; difficulties sitting, lying, crawling, and walking in infants and toddlers

Toe walking

Toe walking

Difficulty in chewing or swallowing

Difficulty chewing or swallowing

Unusual postures

Unusual postures

Areflexia

None described

Tremors in general, tremors of the face and tongue, hand tremors

None described

Mercury Poisoning

Autism

Some aspect of mental impairment in all symptomatic cases

Some aspect of mental impairment in all cases

Borderline intelligence on testing among previously normal individuals; mental retardation occurring in severe cases of pre-/postnatal exposure; some cases of MR reversible; primate studies indicate core intelligence spared with low exposures

Borderline intelligence or mental retardation on standard tests among previously normally appearing infants; some cases of MR "reversible"; indications that normal IQ might be present in MR-labeled individuals

Uneven performance on subtests of intelligence

Uneven performance on subtests of intelligence

Verbal IQ higher than performance IQ; compromised language/verbal expression and comprehension

Verbal IQ higher than performance IQ; compromised language/verbal expression and comprehension

Poor concentration, shortened attention span, general lack of attention; poor response inhibition

Lack of concentration, short attention span, lack of attention, difficulty shifting attention

Forgetfulness, loss of memory, particularly short term, verbal and auditory memory; mental confusion

Poor short term/working memory; poor auditory and verbal memory; lower verbal encoding abilities

Poor visual and perceptual motor skills, poor eye-hand coordination; impairment in simple reaction time

Poor visual and perceptual motor skills, poor eye-hand coordination; lowered performance on timed tests

Not reported as being tested

Difficulty processing multiple stimuli

Difficulty carrying out complex commands

Difficulty carrying out multiple commands

Alexia (inability to comprehend the meaning of written words)

Hyperlexia (ability to decode words while lacking word comprehension)

Deficits in constructional skills, conceptual abstraction, understanding abstract ideas and symbolism; degeneration of higher mental powers

Deficits in abstract/conceptual thinking, symbolism, understanding other's mental states; impairment in sequencing, planning, organizing

Lack of understanding of object permanence (primates)

Deficient understanding of object permanence (children)

Mercury Poisoning

Autism

Stereotyped sniffing (rats)

Stereotyped, repetitive behaviors

Hyperactivity (rats); poor response inhibition (humans), restlessness

Hyperactivity; ADHD-traits

Agitation (humans)

Agitation

Insomnia; difficulty falling asleep (humans)

Insomnia; difficulty falling or staying asleep

Eating disorders: anorexia, poor appetite, food aversion, narrow food preferences, decided food preferences (salty food) (humans)

Eating disorders: anorexia; restricted diet/narrow food preferences; feeding and suckling problems

Masturbation, priapism (children)

Masturbatory tendencies

Unintelligible cries; continuous crying; unprovoked crying (infants and children)

Unprovoked crying

Self injurious behavior, including head banging and hitting the head (toddlers and children)

Self injurious behavior, including head banging and hitting the head

Grimacing (children)

Grimacing

Staring spells (infants and children)

Staring spells

Mercury Poisoning

Autism

Lack of eye contact; difficulties with visual fixation

Lack of eye contact; gaze abnormalities; problems in joint attention

"Visual impairments," blindness, near-sightedness, decreased visual acuity

"Visual impairments"; inaccurate or slow saccades; decreased functioning of the rods; retinal sheen

Light sensitivity, photophobia

Over-sensitivity to light

Blurred or hazy vision

Blurred vision

Constricted visual fields

Not described

Mercury Poisoning

Autism

Increase in cerebral palsy; hyper- or hypotonia; paralysis, abnormal reflexes; spasticity; decreased muscle strength and motor power, especially in the upper body; incontinence; problems chewing, swallowing, and salivating

Increase in cerebral palsy; hyper- or hypotonia; decreased muscle strength, especially in the upper body; incontinence/toilet training difficulties; problems chewing and swallowing

Rashes, dermatitis, dry skin, itching; burning sensation

Rashes, dermatitis, eczema; itching

Autonomic disturbances: excessive sweating; poor circulation; elevated heart rate

Autonomic disturbances: sweating abnormalities; poor circulation; elevated heart rate

Mercury Poisoning

Autism

Gastroenteritis, diarrhea; abdominal pain, rectal itching, constipation, "colitis"

Diarrhea, constipation, gaseousness, abdominal discomfort, colitis

Anorexia, weight loss, nausea, poor appetite

Anorexia; feeding difficulties, vomiting as infants

Lesions of the ileum and colon; increased intestinal permeability

Leaky gut syndrome from sulfur deficiency

Inhibits dipeptidyl peptidase IV, which cleaves casomorphin

Inadequate endopeptidase enzymes responsible for breakdown of casein and gluten

Mercury Poisoning

Autism

Ties up sulfur groups; prevents sulfate absorption

Low sulfate levels

Has special affinity for purines and pyrimidines

Errors in purine and pyrimidine metabolism can lead to autistic features

Depletes cellular tyrosine in yeast

PKU, arising from disruption in tyrosine production, results in autism

Reduces bioavailability of glutathione, necessary in cells and liver for heavy metal detoxification

Low levels of glutathione; decreased ability of liver to detoxify heavy metals

Can cause significant reduction in glutathione peroxidase and glutathione reductase

Abnormal glutathione peroxidase activities in erythrocytes

Disrupts mitochondrial activities, especially in brain

Mitochondrial dysfunction, especially in brain

Mercury Poisoning

Autism

Individual sensitivity due to allergic or autoimmune reactions; sensitive individuals more likely to have allergies and asthma, autoimmune-like symptoms, especially rheumatoid-like ones

More likely to have allergies and asthma; familial presence of autoimmune diseases, especially rheumatoid arthritis; IgA deficiencies

Can produce an immune response, even at low levels; can remain in CNS for years

Indications of on-going immune response in CNS

Presence of autoantibodies (IgG) to neuronal cytoskeletal proteins, neurofilaments, and myelin basic protein; astrogliosis; transient ANA and AnolA

Presence of autoantibodies (IgG and IgM) to cerebellar cells, myelin basis protein

Causes overproduction of Th2 subset; diminishes capacity to produce TNF(alpha) and IL-1; kills lymphocytes, T-cells, and monocytes; inhibits lymphocyte production; decreases NK T-cell activity; may induce or suppress IFN(gamma) and IL-2 production

Skewed immune-cell subset in the Th2 direction and abnormal CD4/CD8 ratios; decreased responses to T-cell mitogens; increased neopterin; reduced NK T-cell function; increased IFN(gamma) and IL-12

Mercury Poisoning

Autism

Primarily impacts CNS

Neurological impairments primary

Selectively targets brain areas - those unable to detoxify heavy metals or reduce Hg-induced oxidative stress

Specific areas of brain pathology; many functions spared

Damage to Purkinje and granular cells

Damage to Purkinje and granular cells

Accummulates in amygdala and hippocampus

Pathology in amygdala and hippocampus

Causes abnormal neuronal cytoarchitecture; interferes with neuronal migration and depresses cell division in developing brains; reduces NCAMs

Neuronal disorganization; increased neuronal cell replication, small glia to neuron ration, increased glial cells; depressed expression of NCAMs

Head size differences: progressive microcephaly

Head size differences: progressive microcephaly and macrocephaly

Brain stem defects in some cases

Brain stem defects in some cases

Mercury Poisoning

Autism

Can increase tissue concentration of serotonin in newborn rats; causes calcium disruptions in neurons, preventing presynaptic serotonin release and inhibiting serotonin transport activities

Serotonin abnormalities: decreased serotonin synthesis in children; over-synthesis in adults; elevated serotonin in platelets; positive response to SSRIs; calcium metabolism abnormalities present

Alters dopamine systems; disrupts calcium and increases synaptosome membrane permeability, which affect dopamine activities; peroxidine deficiency in rats results in acrodynia

Indications of either high or low dopamine levels; positive response to peroxidine by lowering dopamine levels; positive response to dopamine antagonists

Increases epinephrine and norepinephrine levels by blocking the enzyme which degrades epinephrine

Elevated norepinephrine and epinephrine; positive response to norepinephrine reuptake inhibitors

Elevates glutamate; decreases glutamate uptake; reduces functional activity of glutamatergic system

Elevated glutamate and aspartate

Alters choline acetyltransferase, leading to acetylcholine deficiency; inhibits acetylcholine neurotransmitter release via impact on calcium homeostasis; causes cortical acetylcholine deficiency; increases muscarinic receptor density in hippocampus and cerebellum

Abnormalities in cholinergic neurotransmitter system: cortical acetylcholine deficiency and reduced muscarinic receptor binding in hippocampus

Causes demyelating neuropathy

Demyelation in brain

Mercury Poisoning

Autism

Causes abnormal EEGs and unusual epileptiform activity

Abnormal EEG activity; epileptiform activity

Causes seizures, convulsions

Seizures; epilepsy

Causes subtle, low amplitude seizure activity

Subtle, low amplitude seizure activities