Paper 1 in IB Psychology is hard. There are 27 approach topics and 39 context topics. Throw in the six concepts and the combination of content and contexts in Section B and it’s a lot. One way to study smarter not harder is to find topics that overlap. Transcranial magnetic stimulation (TMS) is a perfect example.
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Brain stimulation is both a “biological treatment” for one disorder (depression) and a “treatment for one health problem” (substance abuse). (Image: ChatGPT with info from the IB Psych Guide).
What is TMS?
Transcranial magnetic stimulation (TMS) is a treatment that uses a machine to deliver magnetic pulses to specific parts of the brain. These pulses stimulate neurons and can enhance overall brain functioning. The frequency of the pulses can be adjusted, with higher frequencies generally increasing activity in targeted regions and lower frequencies decreasing it. Although TMS does not directly target specific neurotransmitters like serotonin or dopamine, it can precisely stimulate key areas for health and well-being, like the prefrontal cortex and the nucleus accumbens.
Repetitive TMS (rTMS) is a specific type of TMS that takes place over several weeks. (Image: ChatGPT)
TMS in Addiction
If addiction stems from dysfunction in brain regions such as the prefrontal cortex (PFC) and the nucleus accumbens (NAc), then stimulating and improving activity in these areas may help treat it. In this way, TMS might be getting at one root cause of addiction. For example, one key function of the PFC are to think through the consequences of our actions. It’s like the brain’s breaks on our behaviour. If you have poor function in your PFC, you are less able to consider the consequences of your actions, like taking drugs.
The NAc is the brain’s pleasure centre – it has a high concentration of dopamine receptors and is activated when we do pleasurable things. If you have poor functioning in your NAc, everyday activities won’t seem as enjoyable because you’ll have a lower level of dopamine activation. According to the dopamine hypothesis of addiction, this increases your risk of substance abuse. If TMS can increase the activity in the NAc, however, it might mean everyday life is more enjoyable and the temptation to turn to drugs is reduced.
One meta-analysis of rTMS as a treatment for opioid use disorder found rTMS had medium to large effect sizes in reducing substance use and cravings. The results were most effective when the dorsolateral PFC was targeted. (Mehta et al., 2023).
Improving function in the PFC could help people control their behaviour and stop doing things they regret.
TMS in Depression
Before it was used for addiction, TMS has been used to treat depression. It’s the exact same machine using the same therapeutic principle – stimulate and activate parts of the brain that might be hypo-functioning. As with addiction, TMS is effective when the dorsolateral PFC is targeted. One function of dlPFC is to regulate our emotional responses. It does this by exercising a top-down control over other areas of the brain, like the amygdala. This means if something upsets us, our mind starts to drift into negative thought patterns, the dlPFC can control these through patterns and redirect them. However, if you have hypo(low)-functioning in this brain region, you might end up stuck in these negative thought patterns. This could be why TMS’s activation of the dlPFC is helpful in treating depression.
There’s research supporting TSM as a treatment for depression, too. For example, “many randomized clinical trials have shown that daily TMS of the left prefrontal cortex was effective in treating depressive mood symptoms.” (Rizvi and Khan, 2019).
TMS is also safer (and less scary) than electroconvulsive (shock) therapy (ECT). Amazingly, ECT is still used today for treatment resistant depression – when people have tried everything else and failed to see improvements, they might turn to ECT. ECT involves giving the patient electric shocks around 70-120 volts. But which one’s better I hear you ask?
Psychologists Zara Thurstan and Declan Hyland wanted to know if one was better than the other – TMS or ECT? They analysed six studies that directly compared TMS with ECT. Their findings suggest that “ECT has a superior short-term anti-depressive effect compared with TMS.” They concluded that “ECT remains the most effective short-term treatment for depression.” However, they also point out it’s “need for general anaesthesia and seizure induction may limit its acceptability.” (Thurstan and Hyland, 2025).
Improving PFC function could help someone control their thoughts and emotions and prevent rumination.
Essay Tips
- Biological treatment: TMS is directly targeting areas of the brain, which is why it’s considered a biological treatment for major depressive disorder.
- Treatment for a health problem: Because it’s used to treat substance abuse, it can also be used in an essay question about treatment for a health problem.
- Do note write about depression for questions on health problems and vice-versa – do not write about substance abuse if the question is on mental health.
- Mental health = Depression
- Health problem = Substance abuse
References
Mehta, D. D., Praecht, A., Ward, H. B., Sanches, M., Sorkhou, M., Tang, V. M., Steele, V. R., Hanlon, C. A., & George, T. P. (2024). A systematic review and meta-analysis of neuromodulation therapies for substance use disorders. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 49(4), 649–680. https://doi.org/10.1038/s41386-023-01776-0
Rizvi, S., & Khan, A. M. (2019). Use of Transcranial Magnetic Stimulation for Depression. Cureus, 11(5), e4736. https://doi.org/10.7759/cureus.4736
Thurstan, Z., & Hyland, D. (2025). A Comparison of the Efficacy of Electroconvulsive Therapy and Transcranial Magnetic Stimulation in the Treatment of Depressive Disorder – Is One Better Than the Other?. BJPsych Open, 11(Suppl 1), S41. https://doi.org/10.1192/bjo.2025.10140
Travis Dixon has been teaching for over 20 years and is an experienced IB Psychology, History and English teacher, author, workshop leader and examiner