Sleep disorders have been shown to increase the risk of dementia. This particular aspect may affect the cognition of the patient, leading to behavioral disorders and depression. In early symptomatic Alzheimer’s Disease (AD), Default Mode Network (DMN) disruption occurs and progresses along with the course of the disease. This review mainly focuses on the leading causes of AD along with management of conditions like insomnia, obstructive sleep apnea, night-time sleep duration, Circadian Rhythm Disorder (CRD), neuroendocrine alternation, and impaired sleep to prevent the use of drugs that can cause complications, especially falls or additional cognitive deficits. Moreover, this study highlights the identification of molecular mechanisms like the effect of impaired sleep on amyloid β (Aβ) and tau dynamics, impaired proteostasis, along with appropriate measures to treat few contributing factors that lead to insomnia in AD or Mild Cognitive Impairment (MCI).