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If you’re considering Transcranial Magnetic Stimulation (TMS) or have recently started treatment, you may have heard about the “TMS dip,” which is a temporary increase in depression or anxiety symptoms during treatment. A TMS dip is a known side effect and does not mean your treatment isn’t working.
In this blog post, we’ll explain what a TMS dip is, why it happens, how long it typically lasts, and what changes occur in the brain during this phase of treatment.
What Is a TMS Dip?
A TMS dip refers to a temporary worsening of mood or symptoms that some patients experience during their course of treatment.
During a TMS dip, patients may notice:
- Increased depression symptoms
- Increased anxiety
- Fatigue
- Irritability
- Lower motivation
- Emotional sensitivity
- Feeling like treatment has “stopped working”
Not every patient experiences a TMS dip, and the severity varies from person to person.
When Does a TMS Dip Usually Occur?
Most TMS dips occur between:
- Week 2 and Week 4 of treatment
- Approximately sessions 10–20
Some patients never experience a dip, while others notice only mild changes lasting a few days.
TMS Dips During Accelerated TMS Treatment
Patients undergoing accelerated TMS may also experience a temporary TMS dip, but the timing often differs from a standard treatment schedule.
Instead of occurring around weeks two to four, a dip during accelerated TMS may develop within the first several days of treatment or shortly after completing the accelerated protocol.
Patients may notice increased fatigue, heightened anxiety, irritability, low mood, or emotional sensitivity before improvement becomes more consistent.
Why Does a TMS Dip Happen?
Although researchers are still studying the exact cause, the current understanding is that a TMS dip occurs as the brain actively reorganizes its neural networks.
Unlike medications that gradually alter neurotransmitter levels throughout the brain, TMS directly stimulates specific brain circuits involved in mood regulation.
As these circuits adapt to repeated stimulation, temporary mood fluctuations may occur before more stable improvements emerge.
The Science Behind a TMS Dip
One of the primary goals of TMS is to promote neuroplasticity, the brain’s ability to reorganize and strengthen neural connections.
Repeated stimulation of the dorsolateral prefrontal cortex (DLPFC) leads to several biological changes, including:
- Increased glutamate activity
- Improved communication between neurons
- Long-term potentiation (LTP) of neural pathways
- Changes in functional connectivity between mood-regulating brain regions
- Gradual normalization of activity within the prefrontal cortex and limbic system
During this period of remodeling, the brain is adjusting to new patterns of activity. Similar to beginning a new exercise program, temporary discomfort may occur before long-term improvements become noticeable.
What Happens in the Brain During a TMS Dip?
Several brain regions involved in mood regulation are affected during treatment.
Dorsolateral Prefrontal Cortex (DLPFC)
Amygdala
TMS increases activity within the left DLPFC, a region responsible for:
- Motivation
- Emotional regulation
- Executive function
- Decision-making
As the prefrontal cortex strengthens its communication with the amygdala, emotional processing begins to change. During this adjustment period, some patients may temporarily experience heightened emotional sensitivity as the brain reaches a new balance.
Neurotransmitter Changes
Research suggests TMS influences several neurotransmitters involved in mood regulation, including:
- Glutamate
- GABA
- Dopamine
- Serotonin (indirectly)
These changes develop gradually over multiple treatment sessions rather than after a single treatment.
How Long Does a TMS Dip Last?
Most TMS dips last a few days to a couple of weeks. For many patients, symptoms begin improving shortly afterward as neuroplastic changes become more established.
The duration varies depending on:
- Diagnosis
- Treatment protocol
- Individual brain biology
- Medication changes
- Stress levels
- Sleep quality
Does a TMS Dip Mean Treatment Isn't Working?
Experiencing a TMS dip does not mean treatment has failed. Many patients who ultimately achieve significant improvement report experiencing temporary symptom fluctuations during treatment.
Likewise, many patients improve without experiencing a dip at all. The presence—or absence—of a TMS dip does not reliably predict treatment outcome.
How Can You Manage a TMS Dip?
If you believe you’re experiencing a TMS dip:
- Continue attending your scheduled treatments unless advised otherwise.
- Inform your TMS technician or psychiatrist about any changes in symptoms.
- Maintain a consistent sleep schedule.
- Stay physically active when possible.
- Continue taking prescribed medications unless instructed otherwise.
- Lean on your support system during this temporary period.
Because your treatment team monitors your progress throughout therapy, they can determine whether adjustments to your treatment protocol are appropriate.
When Should You Contact Your Provider?
While mild symptom fluctuations are common, contact your treatment team immediately if you experience:
- Suicidal thoughts
- Severe worsening depression
- New or concerning neurological symptoms
- Medication side effects
- Significant changes in sleep or behavior
Your provider can determine whether your symptoms represent a typical TMS dip or require further evaluation.
Frequently Asked Questions
Does everyone experience a TMS dip?
No. Many patients improve steadily without noticing a temporary worsening of symptoms.
Is a TMS dip a good sign?
A TMS dip is neither inherently good nor bad. It simply reflects that some patients experience temporary fluctuations in symptoms as the brain adapts to treatment.
Can anxiety worsen before it improves?
Yes. Some patients receiving TMS for anxiety report temporary increases in anxiety before experiencing symptom relief.
How long until TMS starts working?
Many patients begin noticing improvement between weeks 3 and 5, although response times vary depending on the individual and treatment protocol.
Final Thoughts
A TMS dip can feel discouraging, but for many patients it represents a temporary phase during the brain’s process of adapting to treatment. By promoting neuroplasticity and strengthening communication within mood-regulating brain circuits, TMS aims to create lasting improvements rather than temporary symptom relief. There are also cases of unknown origin that warrant mentioning .
If you have concerns about your progress during treatment, discuss them with your TMS provider. Your treatment team can help determine whether what you’re experiencing is part of the normal treatment process or requires adjustments.
Dr. Thomas Hughes is an adolescent and adult interventional psychiatrist. He is the owner and founder of Heard Medical and NeoPsych in Glendale, CA. He specializes in medication management and Transcranial Magnetic Stimulation for depression, anxiety, OCD, and PTSD.
Esha Nushrat is a pre-medical student interested in Neurology. She has been working in mental health and volunteers at organizations such as Stride in Recovery and NAMI