How Electrochemical Measurements in the Brain Have Shaped Our Understanding of Depression

Mental health disorders, such as depression, represent a growing global challenge. Depression is difficult to diagnose and treat. These difficulties stem from an insufficient understanding of the underlying mechanisms of the disorder. It is incredibly challenging to improve diagnostic and therapeutic approaches without a clear understanding of depression pathology. Neurotransmitters are low in concentration and fluctuate rapidly, making them difficult to investigate. Progress in methods to study the brain has uncovered clues to the pathology of depression and antidepressant mechanisms. In this review, we first describe the three medical hypotheses of depression: the monoamine, plasticity, and inflammation theories. We highlight key analytical methods that have been employed in depression studies. Lastly, we show how these investigations have advanced our knowledge of depression mechanisms and treatment strategies. Thus, via this review, we present the status quo of how chemical measurements are guiding our understanding of the chemical underpinnings of depression and pointing the community toward new antidepressant treatment targets.