It can be caused by another disorder, by changes in the sleep environment, by the timing of sleep, severe depression, or by stress. Its consequences – sleepiness and impaired psychomotor performance – are similar to those of sleep deprivation. Acute insomnia is the inability to consistently sleep well for a period of less than a month. Insomnia is present when there is difficulty initiating or maintaining sleep or when the sleep that is obtained is non-refreshing or of poor quality. These problems occur despite adequate opportunity and circumstances for sleep and they must result in problems with daytime function. Acute insomnia is also known as short term insomnia or stress related insomnia. Chronic insomnia lasts for longer than a month. It can be caused by another disorder, or it can be a primary disorder. Common causes of chronic insomnia include persistent stress, trauma, work schedules, poor sleep habits, medications, and other mental health disorders. People with high levels of stress hormones or shifts in the levels of cytokines are more likely than others to have chronic insomnia. Its effects can vary according to its causes. They might include muscular weariness, hallucinations, and/or mental fatigue. Prevention
Prevention and treatment of insomnia may require a combination of cognitive behavioral therapy, medications, and lifestyle changes.Among lifestyle practices, going to sleep and waking up at the same time each day can create a steady pattern which may help to prevent insomnia.
This makes the blood leak out of the arteries, causing pressure to the brain and subsequent headaches. Over the last six decades since the disease was first described,  pathogenesis of moyamoya disease remained elusive, although the gene ring finger protein 213 (RNF213) has been implicated. In September 2021, a south Indian researcher has proposed a pathbreaking theory on moyamoya pathogenesis. Coined the "Mechano-biological theory", the disease has a multifactorial pathogenesis. The authors provide a tangible explanation of the occurrence of moyamoya phenomenon in the idiopathic and syndromic variants of the disease. In short, the authors report that moyamoya disease likely occurs due to a number of factors (e.g., differences in vascular anatomy) that ultimately contribute to broad cerebral blood vessel occlusion and consequent shifts in vessel connections to try to provide blood for the compromised brain.Once it begins, the vascular occlusion tends to continue despite any known medical management. In some people this leads to transient ischemic attacks or repeated strokes with severe functional impairment or even death. In others, the blockage may not cause any symptoms.The disease causes constrictions primarily in the internal carotid artery, and often extends to the middle and anterior cerebral arteries, branches of the internal carotid artery inside the skull. When the internal carotid artery becomes completely blocked, the fine collateral circulation that it supplies is obliterated. Patients often survive on the collateral circulation from the back (posterior) of the circle of Willis, arising from the basilar artery.The arterial constrictions in moyamoya disease are unlike the constrictions in atherosclerosis.