The aim of the study is to show that auriculotherapy is effective in the treatment of chronic insomnia.

Chronic insomnia affects a significant proportion of the French population with an estimated prevalence between 15% and 20%.

This disease is mainly managed by general practitioners for whom benzodiazepines and Z-drugs (zopiclone, zolpidem) represent the first-line treatment. The french health authorities recommend limiting the consumption of these molecules to 2 to 4 weeks taking into account their possible undesirable effects (eg memory impairment, in the elderly, road accident) as well as the risk of tolerance and addiction. However, it appears that a majority of the patients concerned become chronic consumers.

The investigators propose to assess cryo-auriculotherapy in the treatment of chronic insomnia.

The population studied will consist of patients with chronic insomnia, whose diagnosis has been made according to the definition in the diagnostic and statistical manual of mental disorders (DSM-5), and followed up in an outpatient clinic at Foch Hospital or in one of the participating centers.

Half of the patients will be treated with cryo-auriculotherapy (use of a device with nitrous oxide) and compared with control patients who will have the same treatment visits involving a sham device (device without nitrous oxide).

Inclusion Criteria:

• Suffering from chronic insomnia as defined in the diagnostic and statistical manual of mental disorders (DSM-5)
• Score ≥ 15 on the Insomnia Severity Index (ISI) questionnaire;
• Covered by a national healthcare insurance
• Consent form signed

Exclusion Criteria:

• Pregnant woman or pregnancy planned for the duration of the study;
• Regular night work or shift work / reversal of sleep patterns;
• Trans meridian travel during the previous month or planned during the study period;
• Unstable or untreated psychiatric disorder including severe depression, severe addiction, unbalanced bipolar disorder;
• Taking insomnia-inducing drugs (eg Corticoids);
• Hypnotic treatment or antidepressant treatment with hypnotic aim introduced since less than 4 weeks or with change dating back less than 4 weeks;
• Presence of organic comorbidities which may be responsible for sleep disorders (SAS and restless legs syndrome): (STOP-BANG) score ≥ 5;
• History of central neurological disorders or progressive brain injury;
• Contraindication to the use of auriculotherapy (lesion or infection of the pinna) by cryotherapy (skin scarring disorder, risk of hypo or hyperpigmentation);
• Treatment by auriculotherapy or acupuncture in this indication in the previous 12 months;
• Previous treatment with cryo-auriculotherapy
• Having started in the month preceding the first auriculotherapy session, any new treatment likely to interfere with the study: specific drug treatment (antidepressant, morphine or anticonvulsant) or complementary therapy (psychological care, physiotherapy, balneotherapy, etc.).
• Difficulty complying with the treatment, questionnaire or study protocol.
• Be deprived of liberty or under guardianship.