Accelerating Transcranial Magnetic Stimulation Treatment for Depression

What's the science?

Thirty percent of people with depression are resistant to treatments like anti-depressant medication or psychotherapy. Some people with treatment-resistant depression respond to repetitive transcranial magnetic stimulation (rTMS) treatment. This technique involves inducing a magnetic field using pulses from a magnetic coil in a device resting on the scalp. However, it might take a patient many weeks of rTMS to see mood improvement, so having a faster acting treatment for those with severe depression is optimal. This week in Neuropsychopharmacology, Fitzgerald and colleagues tested a new ‘accelerated rTMS’ paradigm, to see if the same effects could be achieved faster.

How did they do it?

The authors conducted a randomised controlled trial, in which adults with depression received 63 00 rTMS pulses in total over the course of several rTMS sessions. Pulses were targeted at the dorsolateral prefrontal cortex, known to be involved in emotion regulation.  Fifty-eight adults followed the accelerated schedule: They received 3 treatments per day, for 3 days the first week, 3 treatments over 2 days the second week, and 3 treatments in one day the third week. Fifty-seven adults followed a standard schedule (not accelerated): one treatment per day, 5 days a week, for 4 weeks. They measured depression scores 1, 2, 3, 4, and 8 weeks after treatment.

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What did they find?

Depression scores slowly decreased over the 8-week period in both the accelerated and standard treatment groups. The accelerated treatment did not appear to improve mood faster than the standard treatment, and participants in the accelerated group were more likely to experience discomfort such as headache. There were no differences in the efficacy of the accelerated treatment versus the standard treatment, indicating the accelerated treatment worked just as well as the standard treatment.

What's the impact?

This is the first randomised controlled trial to test whether accelerated rTMS could be used as a treatment for depression. This study clarifies the effectiveness of  accelerated rTMS as a treatment for depression. Accelerated rTMS might be a viable option for individuals with depression who cannot commit to long periods of daily rTMS treatment. Depression comes in many different forms, so determining which treatments work best for which patients, and their potential side effects, is critical for treatment optimization.

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Reach out to study author Dr. Paul Fitzgerald on Twitter @PBFitzgerald

P.B. Fitzgerald et al., Accelerated repetitive transcranial magnetic stimulation in the treatment of depression. Neuropsychopharmacology. (2018). Access the original scientific publication here.

Hunger Affects Brain Activation in Response to Food Across the Lifespan

What's the science?

In adults, brain activity in response to food cues has been shown to predict overeating and weight gain. We do not yet understand the relationship between the brain’s response to food and overeating across the lifespan, including in children, who are especially vulnerable to food cues. Recently in Neuroimage, Charbonnier and colleagues show how certain brain regions activate in response to food depending on hunger level in different age groups.

How did they do it?

They recruited children, teens, adults and elderly participants who were scanned twice using functional MRI, once in a hungry state after fasting all night and once in a full (‘sated’) state after being fed.  Before the scan, participants rated how much they liked various foods. In the scanner, participants performed a food-viewing task where they viewed images of high and low calorie foods. The viewing of non-food images was a control task. Brain activity was compared while participants viewed high versus low calorie foods, in the hungry or full state, across different age groups.

What did they find?

Brain activation in the hungry state was greater across the lifespan when viewing high calorie foods (compared to low calorie foods) in two regions of the prefrontal cortex: the dorsolateral prefrontal cortex (involved in controlling actions) and the dorsomedial prefrontal cortex (involved in processing reward and value). Hunger state alone did not affect brain activation when viewing food. Age also did not affect brain activation for high compared to low calorie foods, even though younger participants rated liking high calorie food more.

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What's the impact?

This is the first study to look at the effects of hunger and different food cues on brain activation in different age groups. The activation of the dorsolateral prefrontal cortex could reflect inhibition of eating, whereas the dorsomedial prefrontal cortex could be activating to process the reward value of the food, however this needs to be investigated further. It is important to understand brain mechanisms for eating behaviors across the lifespan in order to develop strategies to prevent obesity.

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Reach out to study author Dr. Daniel Crabtree on Twitter @DanielCrabtree9

L. Charbonnier et al., Effects of hunger state on the brain responses to food cues across the life span. Neuroimage. 171, 246–255 (2018). Access the original scientific publication here.