This is a randomized, multi-center, open-label study in which patients with depression who responded to an open-label treatment with intermittent theta burst stimulation (iTBS) will receive this procedure as maintenance therapy. The patients will be randomized to two study arms. The arms differ in the frequency of stimulation (standard iTBS (5 treatments every working day for one week) vs. accelerated iTBS (5 treatments in one day)). For purposes of effect size estimation an interim analysis will be done after half of the patients.

Inclusion Criteria:

• adult women and men aged 18 to 70 years with an ICD-10 diagnosis of a depressive episode of depressive disorder (F32), recurrent depressive disorder (F33), or bipolar disorder (F31)
• moderate or severe current episode prior to initial open iTBS treatment (HAMD-21 >16 points)
• response to iTBS treatment (either reduction in HAMD score by 50% or score at the end of treatment <11 points)
• no concomitant psychotic symptoms.
• no other relevant psychiatric disorder as assessed by the study physician
• residence in Germany and German speaking that allows understanding of the information provided
• patient is capable of giving consent

Exclusion Criteria:

• fulfillment of the general contraindications for TMS (electrical implants or metallic objects in the body such as pacemakers or insulin pumps).
• severe neurological diseases (e.g., cerebrovascular events, neurodegenerative diseases, epilepsy, malformations of the brain, severe head injury in the history)
• current harmful use or dependence on alcohol, amphetamines, cocaine, benzodiazepines, anticonvulsants, or opiates
• acute suicidality
• pregnancy
• current participation in another study