The cause of mental disorders such as depression remains unknown. However, the idea that neurotransmitter imbalances cause depression is vigorously promoted by pharmaceutical companies and the psychiatric profession at large. We examine media reports referring to this chemical imbalance theory and ask reporters for evidence supporting their claims. We then report and critique the scientific papers and other confirming evidence offered in response to our questions. Responses were received from multiple sources, including practicing psychiatrists, clients, and a major pharmaceutical company. The evidence offered was not compelling, and several of the cited sources flatly stated that the proposed theory of serotonin imbalance was known to be incorrect. The media can play a positive role in mental health reporting by ensuring that the information reported is congruent with the peer-reviewed scientific literature.