sleeplessness       
noun [ U ] uk/ˈsliːp.ləs.nəs/ us/ˈsliːp.ləs.nəs/
 无法睡着,失眠
the condition of not being able to sleep
  The most common symptoms are sleeplessness and depression. 最常见的症状是失眠和抑郁。 
 Some medical conditions can also cause sleeplessness. 一些病症也会导致失眠。 
 See: sleepless
 - More examples
 - Massage assists with stress, sleeplessness or headaches.
 - She suffers from sleeplessness due to arthritic pain at night.
 - I've been experiencing some sleeplessness.