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.
Studies have found that when a depressed mother’s symptoms remit, her children are less likely to show psychiatric symptoms. A new study by Myrna M. Weissman and colleagues in the American Journal of Psychiatry randomized 76 mothers to treatment with escitalopram, bupropion, or a combination of the two, and assessed the impact of the mothers’ treatment on their 135 children (aged 7–17).
There were no significant differences in the mothers’ symptoms or remission, but children’s depressive symptoms and functioning improved more if their mothers received (only) escitalopram. Only in that group was a mother’s improvement associated with her children’s improvement.
Mothers in the escitalopram group reported greater improvement in their ability to listen and talk to their children compared to the mothers in other groups, and the children of the mothers in the escitalopram group reported that their mothers were more caring.
Children of mothers with low negative affect improved significantly, while children of mothers with high negative affect only improved if their mothers were in the escitalopram group.
The authors suggest that for a mother’s improvement to help her children’s symptoms, her anxious distress and irritability must be reduced, and these may be better targeted with escitalopram than bupropion.
Adolescence may be a period of particular vulnerability to the effects of stress. New research by Shannon Gourley indicates a possible mechanism for this vulnerability. When Gourley exposed adolescent mice to low levels of the stress hormone corticosterone (the equivalent to human cortisol), they developed habit-based rather than goal-oriented decision-making, leading to behaviors that resembled human depression, which lasted into adulthood. Adult mice that were exposed to the low levels of corticosterone were not affected by it.
Gourley also used an alternative method of producing these stress responses a second time by silencing the trkB receptor for brain-derived neurotrophic factor (BDNF) in the amygdala and hippocampus of the mice. The depression-like behaviors that resulted, such as lack of motivation, were able to be reversed by treating the mice with 7,8-dihydroxyflavone, a drug that activated the trkB receptor. In the adolescent mice, this treatment had antidepressant effects that lasted into adulthood, even though the treatment stopped earlier.