The reason this type of insomnia is called secondary insomnia is because it’s a symptom or side-effect of something else. It often is caused by a medical reason such as depression, anxiety, migraine, arthritis, heartburn, restless leg syndrome, stroke, and menopause. Even external influences such as caffeine, tobacco, alcohol, and some medicines can cause secondary insomnia.
It is the most common type of insomnia that people suffer from. This type of insomnia tends to last longer and usually requires medical attention. It doesn’t usually go away on its own.
Source: Women’s office