主题词：Tryptophan and brain disorders; Stress Responses and Cortisol; Neuroinflammation and Neurodegeneration Mechanisms; Long-Term Effects of COVID-19; COVID-19 and Mental Health; Gut microbiota and health; Fibromyalgia and Chronic Fatigue Syndrome Research; Maternal Mental Health During Pregnancy and Postpartum; Intensive Care Unit Cognitive Disorders; Alzheimer's disease research and treatments; Mental Health Research Topics; Schizophrenia research and treatment; Sleep and related disorders; Multiple Sclerosis Research Studies; Neuroendocrine regulation and behavior; Bipolar Disorder and Treatment; Treatment of Major Depression; Exercise and Physiological Responses; Cardiac Health and Mental Health; Health, psychology, and well-being; Autoimmune Neurological Disorders and Treatments; COVID-19 Clinical Research Studies; Circadian rhythm and melatonin; Neurogenesis and neuroplasticity mechanisms; SARS-CoV-2 and COVID-19 Research