https://en.wikipedia.org/wiki/GTP_cyclohydrolase_I https://en.wikipedia.org/wiki/GTP_cyclohydrolase_I The deficiency causes problems with amino acid metabolism

https://en.wikipedia.org/wiki/GTP_cyclohydrolase_I https://en.wikipedia.org/wiki/GTP_cyclohydrolase_I The deficiency causes problems with amino acid metabolism, which themselves mess up the brain. The depression was a mere symptom of the underlying disease. When you read the DSM, you realize there are no mental illnesses, just syndromes: sets of signs and symptoms. Except in select few cases, the pathophysiology is unknown.