C-reactive protein, or CRP, is a protein found in blood plasma, the levels of which rise in response to inflammation. In a recent study, levels of CRP were able to predict which of two antidepressants a patient was more likely to respond to.
The 2014 article by Rudolph Uher et al. in the American Journal of Psychiatry reported that low levels of CRP (<1 mg/L) predicted a good response to the selective serotonin reuptake inhibitor (SSRI) escitalopram (Lexapro) while higher levels of CRP predicted a good response to the tricyclic antidepressant nortriptyline, a blocker of norepinephrine reuptake.
The research was part of the Genome-Based Therapeutic Drugs for Depression (GENDEP) study, a multicenter open-label randomized clinical trial. CRP was measured in the blood of 241 adult men and women with major depressive disorder. In the article the researchers say that CRP and its interaction with medication explained more than 10% of the individual variance in response to the two antidepressants.
If these findings can be replicated with these and similarly acting drugs, it would be a very large step in the direction of personalized medicine and the ability to predict individual response to medications.
Bipolar illness affects 4.5% of the US population. According to researcher Kathleen Merikangas, 1.0% have bipolar I disorder, 1.1% have bipolar II disorder, and the remainder have subthreshold symptoms. Mark Frye, Chairman of the Department of Psychiatry at the Mayo Clinic, gave a lecture on antidepressants in bipolar illness at the 2014 meeting of the American Psychiatric Association.
The newest data from meta-analyses indicate that traditional antidepressants that are effective in unipolar depression are not effective in bipolar depression. Some patient groups, especially those with very early onset depression and mixed depression, are at increased risk of switching into mania and making a suicide attempt while taking antidepressants.
Unipolar depressed patients with a genetic variation that produces a short form of the serotonin transporter (5HT-LPRs/s) are at increased risk for depression in adulthood following a history of childhood adversity, and tend to respond less well to antidepressants. Frye found that 5HT-LPRs/s is weakly associated with switching into mania when antidepressants are given to patients with bipolar depression.
At the same symposium, researcher Mike Gitlin reviewed data on combination therapy, which is rapidly becoming the norm, indicating that in most circumstances, it is superior to monotherapy.
Researcher David Miklowitz reviewed the impressive data on the superiority of most forms of targeted psychotherapy or psychoeducation compared to treatment as usual for bipolar depression. He noted his own finding that Family Focused Therapy (FFT) not only is effective in adolescents and adults with bipolar disorder, but also in reducing illness and dysfunction in those with prodromal disorders (such as depression, cyclothymia, and bipolar not otherwise specified) in situations where there is a family history of bipolar disorder.
Eight components of FFT are:
- Recognition of prodromal symptoms and development of treatment strategies for them.
- Recognition and management of stress and triggers using cognitive restructuring.
- Development of a relapse prevention plan and rehearsal of what to do.
- Regularization of sleep.
- Encouragement of treatment adherence with an eye to a good future.
- Enhancement of emotional self-regulation skills, including cognitive restructuring.
- Improvement of family relationships and communication.
- Education about substance abuse avoidance and treatment for that and other comorbidities.
Many of these are also key components of group psychoeducation, cognitive-behavioral therapy, and interpersonal and social rhythms therapy, and all of these are effective in treating and preventing bipolar depression compared to treatment as usual. It is noteworthy that in the research of Francesc Colom, 90% of patients randomized to treatment as usual relapsed within 24 months, while psychoeducation was highly effective in preventing relapses over the next five years.
This editor (Robert M. Post), the discussant for the symposium, emphasized that the main take-away messages of the speakers were: use more lithium, use more caution and fewer antidepressants in treating bipolar depression, use more combination therapy for acute illness and for maintenance, and definitely use more psychotherapy. Read more
Not all patients with unipolar depression respond to the currently available antidepressants. Acetyl-l-carnitine is a compound that enhances mitochondrial function and neuroplasticity and is effective in the treatment of peripheral neuropathy (damage to the peripheral nerves, which sometimes occurs in chemotherapy or diabetes). It is now being investigated as an antidepressant for patients who have not responded to typical antidepressants.
According to a review of the treatment by S.M. Wang et al. published in the Journal of Psychiatric Research in 2014, acetyl-l-carnitine treated depression better than placebo did in four randomized clinical studies. It was better than placebo and equally as effective as the antidepressant fluoxetine and the atypical antipsychotic amisulpride in various studies of dysthymic disorder. It also improved depressive symptoms in people with fibromyalgia and minimal hepatic encephalopathy (liver damage). The usual dose of acetyl-l-carnitine is 1 to 2 grams/day.
Editor’s Note: The role acetyl-l-carnitine will play in treating people with treatment-resistant unipolar or bipolar depression remains to be better clarified.
Vitamin D plays an important role in the nervous system, regulating the production of neurotrophins, calcium channels, and calcium binding proteins, and it may have antidepressant effects. Researchers are learning more about how the vitamin’s effects take place.
At the 2014 meeting of the International Society for Bipolar Disorders, Yilmazer et al. reported that vitamin D treatment increased the production of glia-derived neurotrophic factor (GDNF). Neurotrophins like GDNF enhance the survival and growth of neurons. Since other neurotrophins (i.e. brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEG-F)) are low in depression, vitamin D’s effect on GDNF could be important to its antidepressant effects.
Certain drugs such as ketamine and memantine that work by blocking activity at the NMDA receptor for the excitatory neurotransmitter glutamate have antidepressant effects. D-cycloserine is a drug that has a related mechanism and is being studied as an antidepressant. At high doses the drug acts as an antagonist at the glycine site of the NMDA receptor, blocking glycine’s ability to facilitate glutamate transmission through the receptor.
Joshua Kantrowitz, a researcher at Columbia University, reported at a recent scientific meeting that the rapid-onset antidepressant effects of D-cycloserine could be maintained for eight weeks. Similar findings were published in the Archives of General Psychiatry in 2010 and were reported in another study by Uriel Heresco-Levy in a 2013 article in the Journal of Neuropsychopharmacology.
Glutamate is the major excitatory neurotransmitter in the brain and is important for the development of long-term memory. However, glutamate overactivity may contribute to depression. Decreasing this overactivity (with ketamine, memantine, or D-cycloserine) may produce antidepressant effects.
Psychiatrists most commonly prescribe antidepressants for bipolar depression, but mounting evidence shows that the traditional antidepressants that are effective in unipolar depression are not effective in bipolar disorder. At the 2013 meeting of the American Psychiatric Association, researcher Jessica Lynn Warner reported that among 377 patients with Bipolar I Disorder who were discharged from a hospital, those who were prescribed an antidepressant at discharge were just as likely to be remitted for a new depression than those not given an antidepressant.
The average time to readmission also did not differ across the two groups and was 205 +/- 152 days. Those patients prescribed the serotonin and norepinephrine reuptake inhibitor (SNRI) drug venlafaxine (Effexor) were three times more likely to be readmitted than those not prescribed antidepressants.
These naturalistic data (generated from observations of what doctors normally do and information in the hospital’s clinical notes) resemble those from controlled studies. In the most recent meta-analysis of antidepressants in the treatment of bipolar depression (by researchers Sidor and MacQueen), there appeared to be no benefit to adding antidepressants to ongoing treatment with a mood stabilizer over adding placebo. Randomized studies by this editor Post et al. and Vieta et al. have shown that venlafaxine is more likely to bring about switches into mania than other types of antidepressants such as bupropion or selective serotonin reuptake inhibitors (SSRIs).
In addition, a naturalistic study published by this editor Post et al. in the Journal of Clinical Psychiatry in 2012 showed that the number of times antidepressants were prescribed prior to a patient’s entrance into a treatment network (the Bipolar Collaborative Network) at an average age of 40 was related to their failure to achieve a good response or a remission for a duration of at least six months during prospective treatment.
Editor’s Note: Antidepressants are still the most widely used treatments for bipolar depression, and their popularity over more effective treatments (mood stabilizers and some atypical antipsychotics) probably contributes to the fact that patients with bipolar disorder receiving typical treatment in their communities spend three times as much time in depressions than in manic episodes. Using other treatments first before an antidepressant would appear to do more to prevent bipolar depression. These treatments include mood stabilizers (lithium, lamotrigine, carbamazepine, and valproate); the atypical antipsychotics that are FDA-approved for monotherapy in bipolar depression, lurasidone (Latuda) and quetiapine (Seroquel); and the combination of olanzapine and fluoxetine that goes by the trade name Symbiax.
Evidence from several sources suggests that the SNRI venlafaxine may be a risk factor for switches into mania and lead to re-hospitalizations. Other data suggest that in general, in bipolar depression, augmentation treated with antidepressants should be avoided in several cases: in childhood-onset bipolar depression, in mixed states, and in those with a history of rapid cycling (4 or more episodes per year).
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive treatment that uses a rapidly changing magnetic field to target neurons, creating a weak electric current. It is used to treat depression, strokes, and other neurological and psychiatric conditions. At the 2013 meeting of the American Psychiatic Association (APA), researcher Linda L. Carpenter reported on new findings about the long-term effects of rTMS.
In the new research, which was led by Mark Andrew Demitrack, 307 patients with unipolar depression who had not responded well to previous antidepressant treatment were given rTMS. They were treated in 43 different clinical practices and administered rTMS according to their evaluating physician, following FDA guidelines. Of the 307 patients who began the study, 264 benefited from initial treatments with rTMS, were tapered off rTMS, and agreed to participate in a one-year follow-up period, by the end of which 68% had improved and 40.4% had achieved complete remission as measured by the Clinical Global Impressions scale for severity of illness.
However, some study participants (30.2%) had worsened by the first follow-up assessment at the 3-month mark, and rTMS had to be re-introduced.
We have previously summarized studies on ketamine, which when given intravenously can bring about rapid-onset antidepressant effects. Ketamine is a full antagonist (or a blocker) of the glutamate NMDA receptors. Another drug currently in development may work in a related way.
At a recent scientific meeting, researcher Sheldon Preskorn showed that the compound GLYX-13, a partial agonist at the glycine binding site of the NMDA receptor (meaning it allows partial function of the glycine receptors that aid NMDA receptor function), exerts rapid antidepressant effects like the full antagonist ketamine when administered intravenously compared to placebo. GLYX-13 allows about 25% of the receptor activity of the full agonists glycine or D-serine, and thus might result in a 75% inhibition of NMDA receptor function.
GLYX-13 did not induce any psychotomimetic effects (like delusion or delirium), which are possible with the full NMDA antagonist ketamine. The effects of GLYX-13 appeared within 24 hours, lasted at least 6 days, but were gone by day 14.
Editor’s Note: Long-term effectiveness of ketamine for treatment of depression is unclear, but in addition to its potential psychotomimetic effects, it can also be abused. Whether GLYX-13 may be easier to use, longer-lasting, or safer for longer-term clinical effectiveness remains a key question.
We’ve written before about the rapid-onset antidepressant effects of ketamine, an anesthetic that is used in human and veterinary medicine. At lower doses, intravenous (IV) ketamine can induce antidepressant effects in both unipolar and bipolar depressed patients. When doses of 0.5mg/kg are infused over a period of 40 minutes, antidepressant effects appear within two hours but are short-lived, typically lasting only three to five days. Results have been consistent across studies at Yale University, the Icahn School of Medicine at Mount Sinai, and the National Institute of Mental Health. So far, clinical use has been limited by the short duration of the effects and the required presence of an anesthesiologist, which can be prohibitively expensive for many patients.
In a cover story in the January 2013 issue of Psychiatric Times, Arline Kaplan reviewed new findings about ketamine. The drug is a high-affinity, noncompetitive NMDA-glutamate receptor antagonist. It is not yet FDA-approved for use in depression.
According to a recent article by Murrough and Charney, response rates to ketamine are around 54% and the drug “appears to be effective at reducing the range of depressive symptoms, including sadness, anhedonia [the loss of ability to experience pleasure], low energy, impaired concentration, negative cognitions, and suicidal ideation.”
David Feifel, Director of the Neuropsychiatry and Behavioral Medicine Program at the University of California at San Diego (UCSD), instituted a program there in which patients can receive treatment with ketamine for clinical purposes (rather than for research) after signing detailed informed consent forms and being warned that the treatment is not yet approved for depression and that its effects may be temporary. The UCSD Medical Center’s Pharmacy and Therapeutics Committee, with the support of the anesthesiology department, agreed that nurses may administer the ketamine in an outpatient setting, making the procedure more affordable.
There is still the question of how to make ketamine’s effects last. Read more
Much has been written about the use of selective serotonin reuptake inhibitor (SSRI) antidepressants during pregnancy. In a review of 920,620 births in Denmark (1995 to 2008) that Jimenez-Solem published this year in the American Journal of Psychiatry, no link was found between any of the SSRIs used in any trimester and risk of stillbirth or neonatal mortality. The only exception was a possible association of three-trimester exposure to citalopram and neonatal mortality.
Editor’s Note: These new data may be of importance to women considering antidepressant continuation during pregnancy when there is a high risk for a depressive relapse. A maternal depressive episode (like other stressors such as anxiety or experiencing an earthquake) during pregnancy does convey adverse effects to the child, so appropriate evaluation of the risk/benefit ratio or staying on an antidepressant through a pregnancy is important.