The studies attached provide insight to urinary neurotransmitter testing as well as reviews of clinical studies that highlight the use of urinary neurotransmitter testing. Researchers used neurotransmitter analysis as a biomarker for the examination of various disorders in children and adults including PTSD, attachment, depression, sleep apnea, metabolic syndrome, anxiety, IBD, and focus.
Dr. Manz's original study on Neurotransmitters measured in urine
An Experimental Evaluation on Targeted Amino Acid Therapy with At-Risk Children
Study on NT testing and amino acid therapy in Russian adoptees conducted by Dr. Karyn Purvis, author of The Connected Child.