Treatment emergent affective switch with intermittent theta burst stimulation over right temporo-parietal junction: A case report

A Small, yet notable, risk of treatment emergent affective switch (TEAS) is associatedwith the use of repetitive transcranial magnetic stimulation (rTMS) for treatment of both unipolar and bipolar depression [1,2]. We report the case of a 42-year-old female, diagnosed with major depressive disorder (recurrent) and psychogenic non epileptic seizures (PNES), who showed TEAS with intermittent theta burst stimulation (iTBS). She presented with an episode of low mood, vague pain symptoms such as headache, reduced interest, easy fatigability, disturbed sleep and impaired activities of daily living for one month. During this episode, she also had brief paroxysms of anxiety associated with sudden stiffening of the arms and legs clenching of teeth and unresponsiveness, each lasting about 10 minutes. All these paroxysms occurred at home, in the presence of family members, either while lying on bed or sitting down. These attacks were not associated with tongue bite, physical injury or incontinence. There was no history of bipolar disorder or epilepsy in family members. MRI Brain and video EEG were unremarkable. Over the past 2 years, she had 2 similar episodes of depression with PNES, each lasting for a month. These episodes had resolved completely with a combination of mirtazapine (15mg/day), flupentixol (0.5mg/day) and clonazepam (0.5mg/day). However, in view of the inadequate response to the same regimen for 3 weeks during the current episode, she was offered adjunctive rTMS. The doses of the medications remained the same. rTMS was delivered using MagVenture-MagProR30 device with a figure-of-8 shaped coil. In view of the prominent PNES, excitatory stimulation over right temporoparietal junction (rTPJ, 1 cm lateral to CP4 electrode in the 10e20 international EEG system) was given [3]. Stimulationwas delivered using iTBS administered at 80% resting motor threshold (RMT), which was determined prior to stimulation sessions. She was scheduled to receive 10 rTMS sessions (2 sessions/day) with 600 pulses per session over a period of 7 days. Stimulation parameters and duration of treatment were in accordance with safety guidelines prescribed for TBS. This protocol was approved by the Institute’s ethics committee (Reference.no. SGRR/IEC/13/18, IEC Registration No. ECR/710/Inst/UK/2015/RR-18). Her baseline scores on the Hamilton depression rating scale (HDRS) and the PNES scale were 18 and 22, respectively. She started showing significant improvement in depressive symptoms, sleep and PNES by third session of rTMS. However, by 5th session, she was noted to be overfamiliar, euphoric and talking excessively;