Quetiapine fumarate belongs to a sedative class of antipsychotics. This drug is still commonly used to treat insomnia. Pharmacologically, quetiapine has a sedative and sleep-promoting effect by acting on histamine H1 receptors. However, some studies have found that the difference between quetiapine and placebo in the treatment of insomnia is small, and there are many potential adverse effects associated with quetiapine, including weight gain and cardiometabolic effects. So the research says that the strength of the evidence supporting the use of this atypical antipsychotic for insomnia is low, unless the patient has significant psychiatric symptoms. However, I personally believe that quetiapine can be used in patients with some mood disorders and mild psychiatric symptoms, but it is not recommended as the drug of choice for insomnia, except in cases where other therapeutic drugs are not effective and the patient has significant irritability and agitation.