Another reason to consider organics: A study of 529 teens and preteens linked high exposure to pesticides to a higher risk of depression. University of California San Diego School of Medicine researchers studied children between 11 and 17 years old in the Ecuadorian Andes, the third-largest exporter of roses. The flowers are routinely sprayed with organophosphate insecticides known to affect the human cholinergic system, a key component in the function of the brain and nervous system. Drawing blood samples, the researchers found that teens that had lower levels of acetylcholinesterase enzyme activity resulting from pesticide toxicity showed more symptoms of depression, especially in girls and those younger than 14. The findings back up anecdotal reports from Andeans of a rise in teen depression and suicide.