Nowadays, sleeplessness, in other word is insomnia, has become a hotly discussed topic when life as well as society is being complex more and more. Many researches have been carried out to discover what are causes and effects of this symptom. My writing will soundly focus not only two major causes: life situation and inputs of human body; but also two effects: serious health problems and behavior impact of sleeplessness. They are according to some researches. The first cause of sleeplessness is life situation.It includes stress, depressed, anxious, or other psychological problems. Many people face to several stressful situations in their life, such as word-overloading, unemployment, exam preparation, loss of a loved one, breaking a relationship, divorce, or separation. These cause lead to they must think or feel bad so much that they don’t feel asleep or can’t have a good and comfortable sleep. Uncomfortable bed, blanket, wrap, room temperature (too hot or too cold) and some kinds of pong also contribute to sleeplessness.As far as I know, depression and anxiety are strongly associated with sleeplessness symptom. Besides, anxiety and depression are the most common feeling people usually face to. The other cause of sleeplessness is inputs of human body. They are some kinds of drug people use, alcohol, some kinds of food or drink, etc.Nowadays, there are many people have some diseases, health matter, so they use some kinds of drug, such as: Prednisone, arthritis, hypertension, asthma, medications used to treat high blood pressure etc.At the second analysis, sleeplessness leaves effect on behavior impact. This can contribute to the symptoms of depression and lose confidence. Some investigation show that America people who sleep less than six hours at night are likely to be diagnosed with depression or anxiety. Besides, people have this symptom are easy to have an accident, making a serious mistake, even the risks. When drivers are lack of sleep, serious motor-vehicle-accidents are likely to occur. In addition, sleeplessness makes people reduce the ability to concentrate or focus on a study, work, and other tasks. Moreover, people usually make impaired social interaction after a long time living with sleeplessness.Both causes and effects of sleeplessness have just been analyzed above, major causes are life situation and inputs of human body and serious effects are serious health problems and behavior impact. With all of the above, I hope that people can avoid this worse symptom so as to have a comfortable, healthy, and happy life.