It may also be of note that higher levels of kynurenine may activate the aryl hydrocarbon receptor, which is an important modulator of immune system‐patterned activity, especially as the aryl hydrocarbon receptor has been implicated in depression and may interact with melatonin and different kynurenine pathway products on the mitochondria outer membrane (Anderson & Rodriguez, 2015). The gene discussed is AHR; the disease is depressive symptom measurement.