At the 3rd Annual Meeting of the Transcranial Magnetic Stimulation Society, Canadian researcher Frank MacMaster discussed his study of repeated transcranial magnetic stimulation (rTMS) in 50 children with depression. RTMS is a non-invasive procedure in which an electromagnetic coil is placed against the side of the forehead and magnetic pulses that can penetrate the scalp are converted into small electrical currents that stimulate neurons in the brain. The study was designed to identify biomarkers, or characteristics that might indicate which patients were likely to respond to the treatment. All of the patients received rTMS at a frequency of 10 Hz. Using magnetic resonance spectroscopy (MRS) technology, MacMaster found that children who responded well to rTMS treatment had low levels of the neurotransmitter glutamate at the beginning of the study, but their glutamate levels increased as their depression improved. Children who didn’t improve had higher glutamate levels at the beginning of the study, and these fell during the rTMS treatment.
MacMaster hopes that glutamate levels and other biological indicators such as inflammation will eventually pinpoint which treatments are likely to work best for children with depression. At the meeting, MacMaster said that in Canada, only a quarter of the 1,200,000 children with depression receive appropriate treatment for it. Very little funding is devoted to research on children’s mental health, a serious deficit when one considers that most depression, anxiety, attention deficit hyperactivity disorder (ADHD), bipolar disorder, oppositional behavior, conduct disorder, and substance abuse begins in childhood and adolescence, and early onset of these illnesses has been repeatedly linked to poorer outcomes.
Editor’s Note: The strategy of identifying biomarkers is an important one. MacMaster noted that this type of research is possible due to the phenomenal improvements in brain imaging techniques that have occurred over the past several decades. These techniques include magnetic resonance imaging (MRI) to a resolution of 1 mm; functional MRI; diffusion tensor imaging (DTI), which can depict the connectivity of white matter tracts; and spectroscopy, which can be used to identify chemical markers of neuronal health and inhibitory and excitatory neurotransmitters, and analyze membrane integrity and metabolic changes. These methods provide exquisite views of the living brain, the most complicated structure in the universe. The biomarkers these techniques may identify will allow clinicians to predict how a patient will respond to a given treatment, to choose treatments more rapidly, and to treat patients more effectively.
At the May meeting of the Society of Biological Psychiatry, researcher Deborah Kim gave a talk on the use of repeated transcranial magnetic stimulation (rTMS) for depression in women who are pregnant. In rTMS treatment, an electromagnetic coil is placed against the side of the forehead and magnetic pulses that can penetrate the scalp are converted into small electrical currents that stimulate neurons in the brain. Kim had recently completed an open study of rTMS in pregnant women, in which 70% of the women responded to rTMS. In another controlled randomized study of 30 women (also by Kim), 75% responded to active rTMS and 50% responded to a sham procedure. None of the women included had problems with the fetus or during delivery.
RTMS offers an alternative to women who are reluctant to take antidepressants during pregnancy. Kim cited data by Lee S. Cohen and colleagues in which women taking antidepressants show a 68% relapse rate if they stop taking these medications during pregnancy compared to a 26% relapse rate among those who continue taking antidepressants during pregnancy. Concerns about antidepressants’ potential effects on a fetus may have been overemphasized. Kim summarized the literature on antidepressants in pregnancy, concluding that there is a preponderance of evidence that antidepressants are safe for the mother and fetus, with few serious effects having been observed. Some researchers have been concerned about risks of persistent pulmonary hypertension or autism among offspring of women who took antidepressants during pregnancy, but studies have shown that the absolute risk of either is small. Stay tuned—on Wednesday we’ll discuss a new large and comprehensive study in which most SSRIs showed no link to birth defects, but fluoxetine and paroxetine were associated with risks of certain birth defects.
Editor’s Note: For mild depression during pregnancy, exercise and psychotherapy might be optimal, along with folate and vitamin D3. For moderate depression, omega-3 fatty acids might also be helpful, but it now appears that rTMS would be less risky than electroconvulsive therapy (ECT), which in the past has been a typical recommendation for pregnant women, but which exposes the fetus to the effects of anesthesia and seizure. In her summary Kim recommended that women with a pattern of recurrent depression continue antidepressant treatment, especially since a mother’s depression itself poses non-trivial risks to the fetus.
In a proof-of-concept study presented at the 2015 meeting of the Society of Biological Psychiatry, Charles R. Conway and Peter Nagele showed that an hour of 50% oxygen/50% nitrous oxide reduced depression more than placebo as measured 2 hours and 24 hours later. Twenty patients were randomized to receive the laughing gas combination or a placebo combination made up of 50% oxygen/50% nitrogen. In the laughing gas group, four patients responded to the treatment and three patients achieved remission, compared to only one patient responding in the placebo group.
Like the anesthetic ketamine, which can bring about rapid but temporary antidepressant effects when delivered intravenously, nitrous oxide is an NMDA receptor antagonist.
Vagal nerve stimulation (VNS) is an FDA-approved treatment for both seizures and depression that has resisted other treatments. It requires an operation for the insertion of a stimulator in the chest wall and electrodes on the left vagus nerve in the neck. A new study by Scott T. Aaronson and colleagues presented at the 2015 meeting of the Society of Biological Psychiatry observed severely depressed patients, 494 who received VNS and 301 who received treatment as usual in the community, over a period of five years. The patients who received VNS had greater response rates, they were more likely to have experienced remission, and their remissions lasted longer than those who received treatment as usual. Overall the patients who received VNS had lower mortality rates and suicide rates as well. VNS might be a good option for patients with depression that has not responded to most other treatments.
Patients with rheumatoid arthritis have high levels of the inflammatory proteins known as interleukin-6 (IL-6), which have been implicated in depression and stress. Rheumatoid arthritis is sometimes characterized by depressive symptoms as well. New research by Dai Wang and colleagues presented at the 2015 meeting of the Society of Biological Psychiatry suggests that treating the high levels of IL-6 in rheumatoid arthritis with the human anti–interleukin-6 antibody sirukumab can reduce symptoms of depression and anhedonia (loss of capacity to experience pleasure).
In the study, patients with rheumatoid arthritis and symptoms of depression or anhedonia were randomized to receive either placebo or sirukumab. After 12 weeks, those who received sirukumab had significantly reduced depression.
Editor’s Note: These data are consistent with meta-analyses showing that IL-6 is elevated in depression and with a study by Scott Russo showing that in animals, interfering with IL-6 blocks the development of depression-like behaviors that typically occur after repeated defeat stress (when an animal is subjected to attacks from a larger, more dominant animal).
The hypoglycemic drug pioglitazone is typically used to treat diabetes, but a 2015 study by A. Zeinoddini and colleagues shows that it may improve depressive symptoms in patients with bipolar disorder who do not have type 2 diabetes or the metabolic syndrome (characterized by high weight, cholesterol, triglycerides, and blood pressure).
Forty-four patients with bipolar disorder and a major depressive episode were randomized to receive either 30 mg/day of pioglitazone or placebo as an adjunctive treatment to lithium. Depressive symptoms were lower in the pioglitazone group at weeks 2, 4, and 6 of the six-week study.
No serious side effect occurred in the study, but pioglitazone use is associated with some risks in those using it for diabetes treatment. People taking pioglitazone for longer than a year have shown increased rates of bladder cancer. There is an increased risk of fractures of the upper arms, hands, and feet in female patients. The drug lowers blood sugar, but not enough to be a problem in people not taking other drugs that lower blood sugar. Pioglitazone can also cause fluid retention, worsening congestive heart failure. It can also cause mild weight gain, anemia, and sinus problems.
Repeated transcranial magnetic stimulation is a non-invasive procedure that has been approved for the treatment of severe depression since 2008. In rTMS treatment, a figure-8–shaped electromagnetic coil is placed against the forehead and magnetic pulses that can penetrate the scalp are converted into small electrical currents that stimulate neurons in the brain up to 1.5 cm deep. More recently, in 2013, the Federal Drug Administration approved a device with an H-shaped coil that delivers deep transcranial magnetic stimulation (dTMS). It can stimulate a wider area, and up to 8 cm deep.
Y. Levkovitz and colleagues have published the first double-blind randomized controlled multicenter trial of dTMS, reporting in the journal World Psychiatry that the intervention was effective and safe in patients who had not responded to antidepressant medication.
The study included 212 patients aged 22–68 years. All participants had failed to respond to one to four antidepressants or had not been able to tolerate the side effects of at least two antidepressants during their current episode of depression. The patients were randomized to receive either a sham treatment or 18 Hz dTMS over the prefrontal cortex acutely for four weeks and biweekly for 12 weeks for a total of 20 sessions.
The patients who received dTMS showed significantly greater improvement in symptoms than those who received the sham treatment, with a moderately large effect size of 0.76. Response and remission rates were also better in those who received dTMS. Response rates were 38.4% for the dTMS group versus 21.4% in the sham group. Remission rates were 32.6% for the dTMS group and 14.6% for the sham group. These difference in response remained stable during the three months of the study.
Side effects were minor except for a seizure that occurred when the protocol for the treatment was breached.
In a new study by ESM Eurelings and colleague in the journal International Psychogeriatrics, the inflammatory marker C-reactive protein differentiated between older people with symptoms of apathy versus symptoms of depression. Higher levels of C-reactive protein were found in those with symptoms of apathy. The researchers concluded that apathy may be a manifestation of mild inflammation in elderly people.
Vortioxetine (Brintellix) is a relatively new antidepressant that has a range of effects on serotonin receptors, making it different from selective serotonin reuptake inhibitors (SSRIs), which work only on the serotonin transporter. In multiple studies, it has treated not only depression but also cognitive dysfunction. In a new study led by Atul Mahableshwarkar and published in the journal Neuropsychopharmacology, 10–20 mg/day of vortioxetine reduced symptoms of depression more than placebo and improved performance on tests of cognitive ability more than placebo and another antidepressant, duloxetine.
While depression is often accompanied by cognitive dysfunction, in this study vortioxetine seemed to directly treat the cognitive deficits rather than reducing them by alleviating the depression. The participants were aged 18–65.
Omega-3 fatty acids are found in some green vegetables, vegetable oils, and fatty fish. There is some evidence that omega-3 fatty acid supplements can reduce depression, but researchers are trying to clarify which omega-3s are most helpful, and for whom. A new study in Molecular Psychiatry suggests that depressed people with higher inflammation may respond best to EPA omega-3 fatty acids compared to DHA omega-3 fatty acids or placebo. Researchers led by M.H. Rapaport divided people with major depressive disorder into “high” and “low” inflammation groups based on their levels of the inflammatory markers IL-1ra, IL-6, high-sensitivity C-reactive protein, leptin, and adiponectin. Participants were randomized to receive eight weeks of treatment with EPA omega-3 supplements (1060mg/day), DHA omega-3 supplements (900mg/day), or placebo.
While overall treatment differences among the three groups as a whole were negligible, the high inflammation group improved more on EPA than on placebo or DHA, and more on placebo than on DHA. The authors suggest that EPA supplementation may help relieve symptoms of depression in people whose depression is associated with high inflammation levels, a link common among obese people with depression.
Editor’s Note: These data add to a study by Rudolph Uher et al. in which people with high levels of C-reactive protein responded better to the tricyclic antidepressant nortriptylene, while those with low levels of the inflammatory marker responded better to the selective serotonin reuptake inhibitor antidepressant escitalopram.