Accelerated Intermittent Theta-Burst Stimulation (aiTBS) in Treatment-Resistant Depression of Bipolar II Disorder

Inclusion Criteria:

   1. Participants aged 18 years old to 80 years old with a primary diagnosis of bipolar
   affective disorder II in a current major depressive episode, according to the criteria
   defined in the Diagnosis and Statistical Manual of Mental Disorders, Fifth Fourth
   Edition, Text Revision (DSM-V).

   2. Able to read, understand, and provide written, dated informed consent prior to
   screening. Participants will be deemed likely to comply with study protocol and
   communicate with study personnel about adverse events and other clinically important
   information.

   3. Meet the criteria by Maudsley Staging Method score >=7

   4. Not in a current state of hypomania (as assessed by the Young Mania Rating Scale) or
   psychosis

   5. In good general health, as ascertained by medical history.

   6. Must have a stable psychiatrist during study enrollment, who confirms diagnosis of
   bipolar II disorder.

   7. Must be on a mood stabilizer regimen for 6 weeks prior to study enrollment and agree
   to continue this regimen during study period

   8. Meet the threshold on the MADRS, with a total score of >/=20 at screening/baseline.

   9. TMS Naive

11. For females of reproductive potential: use of highly effective contraception for at
least 1 month prior to screening and agreement to use such a method during study
participation.

12. Agreement to adhere to Lifestyle Considerations throughout study duration.

Lifestyle considerations:

   1. Abstain from becoming pregnant from the screening visit (Visit 1) until after the
   final study visit (Visit 9).

   2. Continue usual intake patterns of caffeine- or xanthine-containing products (e.g.,
   coffee, tea, cola drinks, and chocolate) without significant change for the duration
   of the study.

   3. Abstain from alcohol for at least 24 hours before the start of each MRI and TMS
   session.

Participants who use tobacco products will be informed that use will be allowed only in
between intervention sessions.

Exclusion Criteria:

   1. Primary diagnosis other than bipolar II disorder

   2. Any structural lesion e.g. structural neurological condition, more subcortical lesions
   than would be expected for age, stroke effecting stimulated area or connected areas or
   any other clinically significant abnormality that might affect safety, study
   participation, or confound interpretation of study results.

   3. Metal implant in brain (e.g. deep brain stimulation), cardiac pacemaker, or cochlear
   implants

   4. History of epilepsy or seizures

   5. Shrapnel or any ferromagnetic item in the head

   6. Pregnancy

   7. Autism Spectrum disorder

   8. Any current or past history of any physical condition which in the investigator's
   opinion might put the subject at risk or interfere with study results interpretation

   9. Active substance abuse (<1 week) or intoxication verified by toxicology screen--of
   cocaine, amphetamines, benzodiazepines

10. Cognitive impairment (including dementia)

11. Current severe insomnia (must sleep a minimum of 5 hours the night before stimulation)

12. Current hypomania or psychosis

13. Showing symptoms of withdrawal from alcohol or benzodiazepines

14. A diagnosis of intellectual disability

15. Parkinsonism or other movement disorder determined by Principal Investigator to
   interfere with treatment

16. Any other indication the Principal Investigator feels would comprise data.

17. Current active suicidal ideation or suicide attempt or suicidal behaviors in the last
   6 months

18. Any history of psycho surgery for depression

19. Any history of ECT (greater than 8 sessions) without meeting responder criteria

20. Recent (within 4 weeks of any clinical effect) or concurrent use of rapid acting
   antidepressant agent (i.e., ketamine or a course of ECT)

22. Any history of myocardial infarction, CABG, CHF, or other cardiac history

23. The presence or diagnosis of prominent anxiety disorder, personality disorder or
dysthymia

24. History of intractable migraine

25. Hypomania in the past 6 months.

26. Depth-adjusted aiTBS treatment dose > 65% maximum stimulator output (MSO)

27. Unstable symptoms between screening and baseline as defined by a 30% change in MADRS-C
score.

28. Any other condition deemed by the PI to interfere with the study or increase risk to
the participant