A leaky umbrella has little value: evidence clearly indicates the serotonin system is implicated in depression.
Jauhar S., Arnone D., Baldwin DS., Bloomfield M., Browning M., Cleare AJ., Corlett P., Deakin JFW., Erritzoe D., Fu C., Fusar-Poli P., Goodwin GM., Hayes J., Howard R., Howes OD., Juruena MF., Lam RW., Lawrie SM., McAllister-Williams H., Marwaha S., Matuskey D., McCutcheon RA., Nutt DJ., Pariante C., Pillinger T., Radhakrishnan R., Rucker J., Selvaraj S., Stokes P., Upthegrove R., Yalin N., Yatham L., Young AH., Zahn R., Cowen PJ.
A recent “umbrella” review examined various biomarkers relating to the serotonin system, and concluded there was no consistent evidence implicating serotonin in the pathophysiology of depression. We present reasons for why this conclusion is overstated, including methodological weaknesses in the review process, selective reporting of data, over-simplification, and errors in the interpretation of neuropsychopharmacological findings. We use the examples of tryptophan depletion and serotonergic molecular imaging, the two research areas most relevant to the investigation of serotonin, to illustrate this.