Stressful or depressing conditions
If someone is going through a lot of stress due to whatever reason that they are facing in life makes them go through sleepless nights, then the chances of getting long-lasting or chronic insomnia. If the stress lasts longer and becomes an everyday problem for an individual, then it always leads to cause more insomnia. The people having a condition of staying in stress for longer times might spend more time in over-thinking about little things. Over-thinking prolongs and makes them more stressed, and they spend most of the part of their nights stressing over little things. While on the other hand, the brain is signaling to fall asleep by secreting the sleep hormone, but the depressed person chooses to preoccupy the mind with all the meaningless thinking.