People with mental disorders often have sleep disturbances, and psychiatric disorders tend to be common in patients with sleep disturbances. They can even predict an exacerbation of the disease or the onset of a new crisis in some cases. In recent years, more studies have been carried out on the relationship between alterations in sleep patterns and psychiatric illnesses, finding a significant relationship between these two. Mainly including insomnia, excessive daytime sleepiness, snoring, and sleep apnea.

Obstructive sleep apnea is one of the most common disorders, characterized by interruptions in breathing, caused suddenly during sleep, with a subsequent decrease in oxygen saturation in the blood, causing consequences in the patient's general condition such as daytime sleepiness excessive. Obstructive sleep apnea about psychiatric disorders is not well defined, since most mental disorders include sleep disturbances. The one that has presented the most relationship with sleep apnea is depression and anxiety.

Frequently, sleep disturbances are common in most patients with mental and psychiatric disorders. Approximately 40% of people have insomnia and 46.5% of people with a psychiatric illness report excessive daytime sleepiness. It has been shown that of 100 people who go to a hospital specializing in sleep, two-thirds present some psychiatric disorder.

These studies managed to find a relationship between sleep disorders and psychiatric disorders.

Sleep disturbances can be a diagnostic criterion or symptom involved in the diagnosis of the following pathologies:

1. Depression

2.Posttraumatic stress

3. Generalized anxiety

4. Substance use disorder

5. Panic disorder

​​Due to the great importance of sleep disturbances in psychiatric consultation, there is a strong relationship between these pathologies and the presence of sleep disorders (insomnia, excessive daytime sleepiness, snoring, and sleep apnea). In recent years, more studies have been carried out between alterations in sleep patterns and psychiatric diseases, finding a high association between these two. Obstructive sleep apnea syndrome, leaves consequences in the general state such as excessive daytime sleepiness and is related to depression, taking into account that obstructive apnea affects the quality of life, damage to neurocognitive functioning, decreased productivity work and interpersonal relationships, studies have shown that not adequately treating Obstructive Sleep Apnea brings significant effects on intellectual and verbal functioning, attention and memory. Suicidal ideation and negative mental symptoms that improve after initiation of treatment with oral devices or CPAP have also been reported. It is very important to identify these disorders because they can make it difficult to optimally manage mental illnesses.

Sleep disorders are highly prevalent in neurodegenerative diseases, in which the alterations of the causative disease interact with psychological factors, from the patient's environment.