Alex Lee and Joshua Lee
   Deep inside one’s mind, unraveling through the complexities of one’s brain, one in every five adult Americans are fighting a battle in their own head. Emerging as one of the most alarming health concerns today, mental disorders have been affecting over 57 million Americans over the past century. Since the late 1800s, extensive research has been performed on psychological disorders but even after almost 200 years later, scientists still do not have a clear enough understanding to make affirmative conclusions. Furthermore, a study conducted by Sullivan in 2000 confirmed that 63% of all mental disorder diagnosis is derived from some form of outside influence. This proved to scientists that it is likely that one’s environment is the source of their mental illness. In studies attempting to branch out on this fact, many scientists have researched and found that exposure to environmental toxicants, toxic substances produced by human activities, was a major factor that has detrimental mental health in humans. With this knowledge, scientists identified the two most prevalent toxicants: neurotoxicants and pesticides..
 Firstly, neurotoxicants are human made toxins that cause disruptions to human nerve tissues. The most common examples are lead, a type of metal; ethanol, found in drinking alcohol; and other chemicals, including glutamic acid, nitric oxide, and botulinum toxin. Neurotoxicants are much more prevalent than many people realize. They can be found in renowned locations, permeating  from manufacturing sites, coal mines, construction sites, recycling locations, and even from other sources like electronic devices and automotive vehicles. Scientists first studied the long term effects of neurotoxicants on children and observed that the most common outcomes were both hyperactivity and antisocial behavior. Initially, the identified symptoms were not alarming but later in adulthood, these children were observed to develop disadvantages in their respective personality profiles, schizophrenia disorders, and psychiatric symptomatology. Next, the scientists researched a group of adults. The results were much more immediate: adults that were excessively exposed to neurotoxicants were observed to develop frequent alterations in mood, energy, and irritability.
   Environmental pesticides, however, are not as widespread. The primary sources come from various contaminants to the surrounding soil, water, and other vegetation in green areas, such as parks, gardens, and golf centers. There are several types of pesticides that target specific species: insecticides, pesticides for insects; herbicides, pesticides for plants; and bactericides, pesticides for bacteria. To study the exposure of these pesticides on humans, scientists first tested on mice as test subjects. They found that all of the major types of pesticides reflected detrimental reactions but found that it disrupted neurotransmission in the parasympathetic nervous system: the nervous system responsible for resting conditions. Scientists then used humans that have been excessively exposed to pesticides for research. They found an increase in depressive symptomatology, suicides, and general neuropsychiatric symptomatology- all of which are symptoms for mental conditions like clinical depression and dysthymic disorder.
   With the advancements in public industries, the exposure of environmental toxicants has drastically increased the numbers  of mentally disabled patients over the past century. Recently, psychologists, environmental specialists and epidemiologists have been collaborating to conduct further research on a larger scale. As this issue is not prevalent yet, scientists estimate for it to take up to another 50 years for a possible treatment.
 Even from a small scale, small initiatives have been taken for not just improving the environment, but also to lower the numbers of mentally ill patients in the United States.