This way, decreased ghrelin signaling can also be blamed for the development of obesity-related neuropsychiatric conditions such as anxiety disorders [239], schizophrenia [239], major depression [239,240], epilepsy [241], MS [242,243], ALS [244], Parkinson’s disease [245,246], Huntington’s disease [245,247], and Alzheimer’s disease [239,245,248]. The gene discussed is GHRL; the disease is obesity due to melanocortin 4 receptor deficiency.