Inclusion Criteria:

1. Subjects between 18 and 75 years of age.
2. Subjects with a diagnosis of major depressive episode and currently experiencing a depressive episode according to DSM-5
3. Subjects with an MDI score > 21 at screening
4. Subjects on stable medication and/or psychotherapy for at least 4 weeks before starting the trial.
5. Subjects, who are willing to comply with the scheduled plan and are able to use the device for 1 hour per day for 6 weeks.
6. Subjects who can understand the oral and written study information and willing to sign an informed consent.

Exclusion Criteria:

1. Subjects with a history of photosensitive migraines and/or epileptic seizures
2. Subjects with a known eye disorder that might be sensitive to light treatment.
3. Subjects with a known history of bipolar disorder according to DSM-5 criteria
4. Subjects with suicidal ideation corresponding to a score of 2 or more on the HAM-D 17 scale item 3 or if the patient or investigator is uncertain of the degree of suicidal risk
5. Subjects with current psychotic symptoms. However, subjects with a prior psychotic depression or subjects with an actual psychotic depression episode that at the time of informed consent no longer fulfills the psychosis criteria are allowed to participate.
6. Subjects with current drug or alcohol dependence based on their medical records or the M.I.N.I. interview.
7. Subjects with a known history of borderline personality disorder
8. Subjects currently enrolled in another investigational treatment study.
9. Subjects with progressive neurodegenerative or neoplastic disease.
10. Subjects who are unable to understand the study procedures or handling of the NSS device.
11. Subjects who are pregnant at the time of inclusion or unsafe contraception in women of fertile age