Chemicals and Mental Health
Early life exposure to heavy metals and ‘environmental chemicals’ may not only reduce IQ but also cause schizophrenia and other mental illnesses. It is now recognised that these also cause Alzheimer’s disease.

Psychological studies have suggested that cognitive decline may well have been cast at the dawn of the industrial age! Early studies showed that significant personality differences were found in people living in regions where large numbers of men were employed in coal-based industries from 1813 to 1820. This was the time when the Industrial Revolution was peaking. Neuroticism (for example) was, on average, 33% higher in these areas compared with the rest of the country. But mental diseases continue to increase, and the rate of age-related dementia has already reached epidemic levels.
In the late 1990’s my genetics laboratory performed many studies on the chromosomes of men and women who had been exposed to high levels of agricultural and industrial chemicals. We found that all those with documented exposures had cells with broken chromosomes and we suggested that this probably gave them an increased risk of developing cancer. However, it was also obvious that most of these people had high levels of anxiety and some degree of mental instability but we didn’t understand that it was ‘cause and effect’. Indeed, the mental instability that was caused by the exposures, probably led to some of their claims being ignored by conventional medicine.
Heavy metals, IQ and mental disorders
Exposure to heavy metals, especially lead, is well known to reduce IQ in children. Populations in towns with lead smelters, such as Port Pirie in South Australia, are regularly monitored to evaluate these effects. The effect on intelligence (IQ) is well established but what isn’t well known is that exposure to metals early in life can also cause schizophrenia[i] and other serious mental and behavioural disturbances. Lead exposure in early life also causes autism[ii].
Several of the studies that are now demonstrating these clear associations are using ‘baby teeth’ to measure the levels of heavy metals and these have the advantage of evaluating exposures over time. Although there is also a genetic predisposition to most mental disorders, heavy metals – especially lead, clearly cause serious mental problems.
Alzheimer’s Disease

Age-related dementia has now reached epidemic levels. People who already have autism are 2.6 times as likely to develop Alzheimer’s but we don’t need to have earlier mental problem to develop Alzheimer’s as we age.
There is considerable research relating the development of Alzheimer’s to exposure to heavy metals, especially lead and copper. Finland has by far the highest rates of death from Alzheimer’s at 54.65 deaths/100,000 whereas Singapore has the lowest rate at 0.43 deaths/100,000.
In my book Why We Age[iii] I argue that much of the increase in the rate of Alzheimer’s is related to the introduction of copper pipes in plumbing. Finland’s extremely high rate of Alzheimer’s may be at least partially explained by the problems they have with pipes in their extreme weather conditions. In contrast, Singapore’s very low rate of Alzheimer’s may be associated with NOT using copper in their pipes and having extraordinary vigilance in their plumbing regulations.
While copper could be a major cause of Alzheimer’s and other serious mental decline, there are many other chemicals and metals that are also known to have effects. I have adapted the table found in the table published by Genius & Kelln (2015)[iv] and although some of these substances are still only ‘strong suspects’, it is easily seen that we are all frequently at risk of exposure to many of these chemicals.
Metals | Lead; Mercury; Copper; Arsenic; Aluminium; Zinc or Manganese overload; Tin |
Pesticides | DDE; Aldrin; Chlordane; Heptachlor; Rotenone; Dieldrin; Methyl parathion; Organophosphates; Maneb; Paraquat; Pyrethroids |
Flame retardants | Hexabromocyclododecane; Tetrabromobisphenol-A; Brominated Decabromodiphenyl ether; Chlorinated 2,2,4,4,tetachloromodiphenyl; 6-hydroxy-2,2,4,4 tetabromodiphenyl ether; Trichloroethylene; Carbon disulphide |
Solvents | Toluene; Perchloroethylene. |
Pharmaceuticals | Anaesthetics; Benzodiazepines |
Air Pollution | Air Pollution: Particulate matter; Ozone; Nitrogen dioxide; Cigarette Smoke; Carbon monoxide |
Plasticizers | Phthalate esters Bisphenol A |
Others | PFOS and PFOA Organochlorine compounds Acrylamide Dioxins Formaldehyde Methanol |

Is it too late? Are there any actions we can take?
There is a great deal written about healthy foods and there is little doubt that an everyday diet that incorporates a wide range of fruit, vegetables, high quality protein, nuts and seeds will supply most of the minerals and nutrients we need. We must make sure that we also consume enough of the ‘trace elements’ that are necessary to support all our detoxification systems and these are discussed in Why We Age.
Beyond eating a healthy diet and exercising, we need to try to avoid pollutants in both indoor and outdoor air. Apart from avoiding the use of chemicals that are in the list above, our most accessible defences against pollutants are indoor and outdoor plants. If we live in an area where the outdoor air is polluted, we need to protect our home by growing leafy plants at least around the borders of our property. But indoor plants are also strong weapons against indoor pollutants. Don’t have them in your bedroom at night because they will compete with you for oxygen but use them in all your living areas.
NASA has undertaken extensive experiments that demonstrate the value of indoor plants in removing pollutants. If your indoor plants die, they might well be saving your life and your future sanity!

[i] Modabbernia A et al (2016) Early Life metal exposure and schizophrenia. Eur Psychiatry 36: 1-6.
[ii] Arora M, Reichenberg A, et al 2017. Fetal and postnatal metal dysregulation in autism. Nat Commun; doi: 10.1038/NCOMMS15493
[iii] Ford JH (2019) Why We Age (Solving the Puzzle of Aging) – available from this website or from Amazon https://www.amazon.com/dp/B082KPSFR2.
[iv] Genius SJ & Kelln KL (2015) Toxicant Exposure and Bioaccumulation: A Common and Potentially Reversible Cause of Cognitive Dysfunction and Dementia. Behavioural Neurology http://dx.doi.org/10.1155/2015/620143
Great blog Judy! I’ve always associated toxins with increased cancer risk… now you’ve given me more reason to avoid these substances. It’s horrifying to see how long the list is!!
I also thought we were only worried about cancer and Parkinsons but the neurological and psychological effects are so alarming. Please share the messages.
Thanks Judy. Interesting as always. Going out now. to buy a new Peace Lilly!