HTR4 and depressive symptom measurement: In line with data in animal models that 5HT4 agonists may be beneficial in depression, and also in combination with an SSRI, we are currently exploring the effects of a 5HT4 partial agonist (PF-04995274) on emotional and cognitive function in unmedicated depressed patients (NCT03516604) and patients who have not showed a sufficient response to current SSRI treatment (NCT03515733).