A new study found that living alone increases common mental disorders (CMD) due to sadness. The researchers looked at the data of 20,000 adults from the United Kingdom. After the study period, the number of adults who lived alone increased from 8.8 to 10.7 percent and so did the rate of CMDs from 14.1 to 16.4 percent. The researchers also studied other causes of CMD such as height and weight, level of education, employment status, alcohol and drug use, social support, and feelings of loneliness. The result found that loneliness is the top reason of CMD. Some health psychologist said that the study reveals the importance of social support.