The cause of tension-type headaches is not clear. However, they are thought to be triggered by certain situations, such as:

• stress, emotional tension, depression or anxiety
• poor posture, which causes scalp and neck muscles to tense up
• squinting to read, which causes scalp muscles to tense up
• certain foods
• bright sunlight
• tiredness
• noise
• caffeine
• certain smells
• menstrual periods
• changes in the weather
• daily use of painkillers (the body gets used to the painkillers and a withdrawal headache may occur if painkillers are not taken every day)