It's not always clear what triggers insomnia, but it's often associated with: stress and anxiety a poor sleeping environment – such as an uncomfortable bed, or a bedroom that's too light, noisy, hot or cold lifestyle factors – such as jet lag, shift work, or drinking alcohol or caffeine before going to bed mental health conditions – such as depression and schizophrenia physical health conditions – such as heart problems, other sleep disorders and long-term pain certain medicines – such as some antidepressants, epilepsy medicines and steroid medication