Through many years, the standard care has been to use continuous sedation of critically ill patients during mechanical ventilation. However, preliminary randomised clinical trials indicate that it is beneficial to reduce the sedation level in these patients. The NONSEDA trial is an investigator-initiated, randomised, clinical, parallel-group, multinational, superiority trial designed to include 700 patients from at least six ICUs in Denmark, Norway and Sweden, comparing no sedation with sedation and a daily wake-up trial during mechanical ventilation. This is a substudy of the NONSEDA trial, concerning 250 patients included at trialsite Kolding, Denmark. The aim of the substudy is to assess the effects of no sedation on posttraumatic stress disorder after discharge from ICU.

Our hypothesis is that critically ill patients who are not sedated during mechanical ventilation will have less posttraumatic stress disorder after discharge.

Inclusion Criteria:

• Endotracheally intubated
• Expected time on ventilator > 24 hours
• Age ≥ 18 years
• Informed consent

Exclusion Criteria:

• Severe head trauma where therapeutic coma is indicated
• Therapeutic hypothermia where therapeutic coma is indicated
• Status epilepticus where therapeutic coma is indicated
• Patient has participated in the study before
• Patient is transferred from another ICU with length of stay > 48 hours
• Patient is comatose at admission
• PaO2/FiO2 ≤ 9, if sedation is necessary for oxygenation
• Patient does not speak Danish, swedish or norwegian at a reasonable level