Stepped Care aiTBS 2 Depression Study (Ghent) (aiTBS2-Ghent)

The Effects of Accelerated Intermittent Thetaburst Stimulation Followed by a Cognitive Control Training in Treatment Resistant Unipolar Depressed Patients

Antidepressant-free unipolar melancholic depressed patients (at least stage 2 treatment-resistant) will be selected by a certified psychiatrist, who will administer (semi-)structured clinical interviews. Because concomitant antidepressant treatment can confound outcome results, all patients will go through a medication washout before entering the study and they will be free from any antidepressant, neuroleptic and mood stabilizer for at least two weeks before entering the treatment protocol. Only habitual benzodiazepine agents will be allowed. STEP 1: Patients will be treated with in total 20 accelerated intermittent Theta Burst Stimulation (aiTBS) sessions (3000 pulses/session) over the left dorsolateral prefrontal cortex, which will be spread over 4 days. On each stimulation day, a given patient will receive 5 sessions with a between-session delay of 15 minutes. Patients will be randomized to receive either the real aiTBS or sham treatment (first week). However, the sham group will receive real aiTBS treatment with 10 days' time interval. The investigators expect that real aiTBS treatment and not sham will result in a significant and clinical meaningful response. STEP 2: To optimize treatment and reduce relapse following the iTBS treatment, in a stepped care approach, all patients then continue with cognitive control training (CCT) ten days later. This CCT consists of 20 sessions, spread over 4 weeks. Patients will be randomized to receive either real CCT or a control training. During this follow-up treatment, all patients will be prescribed antidepressant medication (SSRI) again. As iTBS treatment effects are known to decline over time, the investigators expect that combining aiTBS with a follow-up CCT therapy will stabilize the clinical effects over time compared to receiving the iTBS treatment alone. For baseline comparisons, patients will be closely matched for gender and age with never-depressed, medication-free healthy volunteers. No volunteer will undergo treatment.

Major depressive disorder, Treatment resistant depression, Accelerated intermittent thetaburst stimulation, Cognitive control training, Neuroimaging

Patients receive active aiTBS treatment in the first week, and starting from week 3 receive active CCT for a period of 4 weeks in combination with an antidepressant (SSRI)

Patients receive active aiTBS treatment in the first week, and starting from week 3 receive a control training for a period of 4 weeks in combination with an antidepressant (SSRI)

Patients receive sham aiTBS treatment in the first week, real aiTBS treatment in the third week, and starting from the fifth week receive CCT for a period of 4 weeks in combination with an antidepressant (SSRI)

Patients receive sham aiTBS treatment in the first week, real aiTBS treatment in the third week, and starting from the fifth week control training for a period of 4 weeks in combination with an antidepressant (SSRI)

In the active aiTBS arm, the patients will receive 100 cycli of thetaburst trains of 2s, separated by an inter-train-interval of 6 seconds, delivered on the left dorsolateral prefrontal cortex (DLPFC; i.e. 3000 pulses per session). On each stimulation day, a given patient will receive 5 sessions with a between-session interval of 15 minutes. The treatment protocol of in total 20 aiTBS sessions will be spread over 4 days (i.e. 60.000 pulses in total). The sham coil has been specifically developed to mimic the real one.

By training working memory processing, the CCT aims at modulating similar prefrontal cortex regions as being stimulated previously by aiTBS, namely the DLPFC. thereby possibly stabilizing clinical effects of aiTBS over time. In total 20 sessions of CCT vs. control training (of approximately 25 minutes per session), will be spread over a period of 4 weeks.

All patients will be prescribed antidepressant medication (SSRI) again when starting the CCT (vs. control training).

Intake, baseline (D0), 3 days after aiTBS or sham (+/-D7), 10 days after aiTBS or sham (+/-D14), [for the sham group 3 days (+/-D21) and 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Intake, baseline (D0), 3 days after aiTBS or sham (+/-D7), 10 days after aiTBS or sham (+/-D14), [for the sham group 3 days (+/-D21) and 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Intake, baseline (D0), 3 days after aiTBS or sham (+/-D7), 10 days after aiTBS or sham (+/-D14), [for the sham group 3 days (+/-D21) and 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Intake, baseline (D0), 3 days after aiTBS or sham (+/-D7), 10 days after aiTBS or sham (+/-D14), [for the sham group 3 days (+/-D21) and 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Baseline (D0), 3 days after aiTBS or sham (+/-D7), 10 days after aiTBS or sham (+/-D14), [for the sham group 3 days (+/-D21) and 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Baseline (D0), 3 days after aiTBS or sham (+/-D7), 10 days after aiTBS or sham (+/-D14), [for the sham group 3 days (+/-D21) and 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Baseline (D0), 3 days after aiTBS or sham (+/-D7), 10 days after aiTBS or sham (+/-D14), [for the sham group 3 days (+/-D21) and 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Baseline (D0), 10 days after aiTBS or sham (+/-D14), [for the sham group 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Baseline (D0), 10 days after aiTBS or sham (+/-D14), [for the sham group 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Baseline (D0), 10 days after aiTBS or sham (+/-D14), [for the sham group 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Baseline (D0), 10 days after aiTBS or sham (+/-D14), [for the sham group 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Baseline (D0), 10 days after aiTBS or sham (+/-D14), [for the sham group 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Baseline (D0), 10 days after aiTBS or sham (+/-D14), [for the sham group 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56), 3 & 6 months follow-up

Changes in functional activity connectivity at rest and during tasks in which self-referential social evaluations are presented via headphones in the scanner

Changes in state-dependent ruminative thinking due to hearing self-referential social evaluations presented via headphones in the scanner - self-report

Before entering the scanner, and following each resting state fMRI (i.e. before hearing self-referential social evaluations and after hearing these evaluations), perseverative thinking will be assessed using the perseverative thinking questionnaire (PTQ).

Changes in state-dependent mood due to hearing self-referential social evaluations presented via headphones in the scanner - self-report

Before entering the scanner, and following each resting state fMRI (i.e. before hearing self-referential social evaluations and after hearing these evaluations), mood will be assessed using visual analogue scales (VAS).

Baseline (D0), 10 days after active aiTBS in both groups (+/-D14 for the active group, +/-D28 for the sham group)

CANTAB battery administration (i.e. motor screening, delayed matching to sample, rapid visual information processing, one touch stockings of Cambridge, spatial working memory).

Baseline (D0), 10 days after aiTBS or sham (+/-D14), [for the sham group 10 days after active aiTBS (+/-D28)], after CCT (+/-D42; for the sham group +/-D56)

Baseline (D0), 10 days after active aiTBS in both groups (+/-D14 for the active group, +/-D28 for the sham group), after CCT (+/-D42; for the sham group +/-D56)

Baseline (D0), 10 days after active aiTBS in both groups (+/-D14 for the active group, +/-D28 for the sham group), after CCT (+/-D42; for the sham group +/-D56)

Baseline (D0), 10 days after active aiTBS in both groups (+/-D14 for the active group, +/-D28 for the sham group), after CCT (+/-D42; for the sham group +/-D56)

Following each of the 20 CCT or control trainings (spread over +/- D15 up to D42 for the active group; spread over +/- D29 up to D56 for the sham group)

Predictive influence of single nucleotide polymorphisms on treatment outcome - genetics using a saliva sample

After the first aiTBS or sham session (D1), after the first CCT or control session (+/- D15 for the active group, +/-D29 for the sham group)

Inclusion Criteria: Antidepressant-free unipolar major depression with melancholic features Not responding to at least two trials with an antidepressant Aged between 18-65 years old Exclusion Criteria: Depression with bipolar/psychotic features Dysthymia Severe personality disorders Active substance abuse/dependence within a year prior to inclusion Pregnancy or without effective anticonception for the duration of the trial ECT non-responder No response to more than 9 antidepressants Any neurological condition Any implanted electronic device susceptible for magnetic field radiation (e.g. pacemaker) Any implanted metal device in the head region Current or past history of epilepsy Neurosurgical interventions Known allergic reaction to radiotracers or associated compounds Healthy volunteers may be accepted as control subjects.