Hi, The causes are Stress. Concerns about work, school, health, finances or family can keep your mind active at night, making it difficult to sleep. Stressful life events or trauma — such as the death or illness of a loved one, divorce, or a job loss — also may lead to insomnia. Travel or work schedule. Your circadian rhythms act as an internal clock, guiding such things as your sleep-wake cycle, metabolism and body temperature. Disrupting your body s circadian rhythms can lead to insomnia. Causes include jet lag from travelling across multiple time zones, working a late or early shift, or frequently changing shifts. Poor sleep habits. Poor sleep habits include an irregular bedtime schedule, naps, stimulating activities before bed, an uncomfortable sleep environment, and using your bed for work, eating or watching TV. Computers, TVs, video games, smartphones or other screens just before bed can interfere with your sleep cycle. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Monish De, Oncologist