PTSD (post-traumatic stress disorder) and MDD (major depressive disorder) are two very serious mental illnesses that are prevalent in the US. It is estimated that 8 percent of Americans, or 24.4 million people, suffer from PTSD, and 6.7 percent, or 16.1 million Americans, suffer from MDD.
However, like many mental illnesses, PTSD and MDD may even manifest in comorbidity—or when an individual has two or more diagnosed disorders or illnesses at the same time or one after the other. Comorbid mental illnesses are especially difficult for individuals to navigate since they are often more resistant to treatment or difficult to pin down.
TMS (transcranial magnetic stimulation) has emerged recently as an effective treatment for comorbid PTSD and MDD. In this article, we’ll discuss:
- What PTSD and MDD are, and what their comorbidity means for individuals
- What TMS treatment is
- What the new EEG-TMS study is and why it matters
PTSD, MDD, and their comorbidity
In this section, we’ll spend some time slowly breaking down PTSD and MDD, the side effects of each, and how their comorbidity manifests.
According to Psychiatry.com, PTSD is “a psychiatric disorder that can occur in people who have experienced or witnessed a traumatic event such as a natural disaster, a serious accident, a terrorist act, war or combat, rape, or any other violent personal assault.”
In American history, especially in the 20th century onward, PTSD has been primarily associated with individuals who serve in the military and may acquire PTSD from the stressful, violent events which they must witness. After World War I, PTSD was often referred to as “shell shock” (a phrase coined by soldiers themselves), or “combat fatigue” or “battle fatigue” after World War II.
However, while combat soldiers certainly make up a portion of those who suffer with PTSD, combat soliders are not the only individuals who can acquire PTSD. PTSD can occur in anyone who has suffered from a traumatic event; it is not barred by gender, ethnicity, race, or nationality.
PTSD diagnosis criteria
To be diagnosed with PTSD, an individual must have had exposure to actual or threatened death, serious injury, sexual violation, etc., which may include:
- Directly experiencing the traumatic events
- Witnessing, in person, the traumatic events
- Learning that the traumatic events occurred to a close family member or close friend; cases of actual or threatened death must have been violent or accidental
- Experiencing repeated or extreme exposure to aversive details of the traumatic events (e.g. first responders collecting human remains; police officers repeatedly exposed to details of child abuse)
According to the ADAA (American Depression and Anxiety Association), PTSD’s symptoms come in three groups, re-experiencing the trauma, emotional numbness and avoidance, and increased arousal.
Re-experiencing trauma (one or more of the following)
- Spontaneous or cued recurrent, involuntary, and intrusive distressing memories of the traumatic events
- Recurrent distressing dreams in which the content or affect (i.e. feeling) of the dream is related to the events
- Flashbacks or other dissociative reactions in which the individual feels or acts as if the traumatic events are recurring
- Intense or prolonged psychological distress at exposure to internal or external cues that symbolize or resemble an aspect of the traumatic events
- Physiological reactions to reminders of the traumatic events
Emotional numbness and avoidance (two or more of the following)
- Inability to remember an important aspect of the traumatic events (not due to head injury, alcohol, drugs)
- Persistent and exaggerated negative beliefs or expectations about oneself, others, or the world (e.g., “I am bad,” “No one can be trusted,” "The world is completely dangerous").
- Persistent, distorted blame of self or others about the cause or consequences of the traumatic events
- Persistent fear, horror, anger, guilt, or shame
- Markedly diminished interest or participation in significant activities
- Feelings of detachment or estrangement from others
- Persistent inability to experience positive emotions
Increased arousal (two or more of the following)
- Irritable or aggressive behavior
- Reckless or self-destructive behavior
- Exaggerated startle response
- Problems with concentration
- Difficulty falling or staying asleep or restless sleep
MDD, simply known as depression, is one of the most common, but serious, mood disorders, affecting over 300 million people worldwide—or 10% of the world population—according to the World Health Organization (WHO).
According to the National Institute of Mental Health (NIMH), some of the symptoms of MDD include, but are not limited to:
- Persistent sad, anxious, or “empty” mood
- Feelings of hopelessness, pessimism, guilt, worthlessness, etc.
- Loss of interest or pleasure in hobbies and activities
- Decreased energy or fatigue
- Moving or talking more slowly
- Feelings of restlessness or trouble sitting still
- Difficulty concentrating, remembering, or making decisions
- Difficulty sleeping, early-morning awakening, or oversleeping
- Appetite and/or weight changes
- Aches, pains, headaches, cramps, or digestive problems without a clear cause
- Thoughts of death or suicide, or suicide attempts
Individuals are at a higher risk for MDD if they:
- Have personal or family history of depression
- Go through major life changes, trauma, or stress
- Have certain physical illnesses and medications
PTSD comorbid with MDD
It is approximated that half of people who suffer from PTSD also suffer from MDD.
A 2014 study testing PTSD-MDD comorbidity in Israeli Yom Kippur war veterans showed that participants with this comorbidity expressed higher levels of dissociation, somatization, self-destructive behavior, and suicidality, rendering the group extremely vulnerable.
Dissociation is “a mental process of disconnecting from one’s thoughts, feelings, memories or sense of identity.
Somatization is a form of mental illness that causes one or more bodily symptoms, including pain. The symptoms may or may not be traceable to a physical cause including general medical conditions, other mental illnesses, or substance abuse.
TMS: What, who, and why
In the next section, we’ll discuss why TMS is emerging as a viable method of treatment for certain mental illnesses, such as comorbid PTSD and MDD. But in this section, we’ll first discuss what TMS is and why it might be used, generally.
What is TMS?
According to Healthline, TMS is “a form of brain stimulation therapy used to treat depression and anxiety. It has been used since 1985. The therapy is non-invasive and uses a magnet to target and stimulate certain areas of the brain, making it a drug-free procedure.
TMS sessions can last from 30 to 60 minutes at a time.
During sessions, TMS patients sit or recline while an electromagnetic coil is held against the head. The doctor will place the coil against the forehead, near the area of the brain which regulates mood. Then, magnetic pulses pass from the coil to the brain, which sparks an electric current in nerve cells.
It is thought that this stimulation of nerve cells may reduce depression.
Who can benefit from TMS?
TMS is commonly employed as treatment for severe, treatment-resistant—i.e. pharmacology and psychotherapy resistant—forms of depression.
Antidepressants and psychotherapy may be used in conjunction with rTMS.
Why choose TMS?
Individuals who are not eligible for electroconvulsive therapy (ECT) may be better candidates for TMS, since ECT has a higher rate for seizures and requires anesthetic inducement. Individuals who are not eligible for electroconvulsive therapy (ECT) may be better candidates for TMS, since ECT has a higher rate for seizures and requires anesthetic inducement.
Also, as mentioned, TMS is a great option for those who have sought treatment (whether in the form of pharmaceuticals, psychotherapy, etc.) and have not been seeing effects. Often, in cases of comorbid illnesses or severe depression, mental illnesses are quite treatment-resistant and difficult to navigate. Treatment resistance may be extremely disheartening or disencouraging for those who have suffered from mental illnesses and are tired of waiting for results.
New EEG study on TMS for comorbid PTSD and MDD
In a recent study published in the Journal of Affective Disorders, it was found that EEG (electroencephalography) data may be used to predict clinical response to TMS in patients with comorbid PTSD and MDD.
It was found that “TMS was associated with significant improvement in both PTSD and depression severity (all P <.05). [Post-treatment] clinical response was achieved on the depression and PTSD self-report scales in 13/29 and 12/29 patients, respectively. Using regression, TMS treatment outcome could be predicted from [pre-treatment] EEG Alpha band coherence. . . The optimal sensitivity for Alpha-trained regression in predicting clinical response was 100% for depression and 94% for PTSD.”
Limitations of the study include that there was a lack of a sham condition, and the cohort was quite small.
Conclusions: What does this mean for PTSD and MDD?
The data suggests that “pre-treatment EEG coherence may be used to predict TMS response in patients with depression and PTSD.” Thus, it may be analyzed whether an individual will respond well to TMS treatment.
While this does not guarantee efficacy of TMS treatment, TMS is still largely effective for treatment-resistant PTSD and depression, proving it to be a promising treatment method for their comorbid manifestation.