There are a number of different types of insomnia characterized by causes and duration. Primary insomnia is a sleep disorder that is not caused by an underlying medical condition, while secondary insomnia is a sleep disorder that is caused by an underlying medical or psychological condition. Primary insomnia is usually caused by factors such as stress, anxiety, depression, or poor sleep habits. Individuals with primary insomnia may find it difficult to fall asleep, stay asleep, or wake up too early. Secondary insomnia can be caused by a variety of factors, including medical conditions such as asthma, arthritis, or chronic pain, as well as psychiatric conditions such as anxiety, depression, or bipolar disorder. Medications, caffeine, alcohol, and drug use can also cause secondary insomnia. Another type of insomnia is acute insomnia, which is a short-term sleep disorder that typically lasts less than three months. Acute insomnia is usually caused by a stressful event or situation, such as a breakup, a job loss, or a death in the family. Chronic insomnia is another type of insomnia that lasts for at least three months. Chronic insomnia can be caused by a variety of factors, including medical conditions, psychological conditions, and poor sleep habits.