Genetic Markers of Response to Lithium
At the 5th Biennial Conference of the International Society for Bipolar Disorders and the 67th Annual Meeting of the Society of Biological Psychiatry, John Kelsoe presented his research on personalized pharmacotherapy for bipolar disorder, describing genetic predictors of response to lithium.
In his research Kelsoe found that a variant of the gene that codes for neurotrophic receptor type II (NTRK2), the receptor for brain-derived neurotrophic factor (BDNF), was associated with good response to lithium in patients with a family history of bipolar disorder or a history of euphoric mania. The “T” allele of rs1387923 was associated with better response to lithium retrospectively, and these results were replicated in a prospective study.
Editors Note: These data are among the first to indicate that genetic information could be used to make treatment decisions. Lithium increases BDNF and neurogenesis, thus it makes some sense that a variation in the BDNF receptor would affect clinical responsiveness to lithium.
In a similar vein, Janusz K. Rybakowski reported at the Society of Biological Psychiatry meeting on another possible predictor of long-term excellent response to lithium in bipolar disorder. Due to normal genetic variation, different people have different versions of BDNF. Rybakowski found that the patients with a version of BDNF known as Val66Val who had bipolar disorder performed significantly better on the Wisconsin Card Sorting Test, which evaluates abstract reasoning. However, he found that patients with a methionine amino acid in the place of one of the valine amino acids (resulting in a Val66Met allele, which is associated with minor cognitive difficulties) showed significantly better response to preventative treatment with lithium. It is noteworthy that these excellent lithium responders also performed better on a complex neuropsychological battery than those who were less good responders to lithium. The good responders’ performance on these tests was not different from healthy controls.
Editor’s Note: These data add to the possibility that prediction of lithium response is linked to common gene variations in neuroprotective factors or their receptors. It is interesting that the patients with the Val66Met allele, which works less efficiently, show the best long-term response to lithium. This is consistent with the view that lithium, which increases BDNF, is most effective in those who have a sluggish functioning of their BDNF due to having the Met allele. As we have written before, those with the Met allele have slight decrements in working memory, and in animal models, those with the Met allele show deficits in long-term potentiation (LTP), which suggest problems with long-term memory. Thus, using lithium to increase BDNF function in those with a “sluggish” variation in their BDNF makes sense and may ultimately be clinically useful.
Creative People More Likely to Have Mental Illness
Mozart
According to a large family study of people with severe mental disorders that was published by Kyaga et al. in the British Journal of Psychiatry last year, people with bipolar disorder and siblings of people with schizophrenia or bipolar disorder were much more likely to be working in creative professions than people without severe mental illness.
Kyaga talked to Medscape Medical News about the study:
“I think the study stresses the importance of treating all patients individually, and with the aim of finding the optimal treatment with regards to effectiveness, while minimizing the adverse effects that medication can have on positive aspects of psychiatric disorders,” Dr. Kyaga said.
“We often encounter the suggestion that lithium reduces creativity in patients with bipolar disorder and that adherence therefore is difficult. Now we can say that it is true that bipolar disorder is in fact associated with increased creativity, but we also know from previous research that terminating treatment with lithium in bipolar disorder will, in the long run, disrupt creative behavior,” he continued.
“We therefore need to pay close attention to what patients tell us while being treated, so that we can find a regimen that will work for them to prevent the disastrous consequences of severe psychiatric disorder, while providing them opportunities to uphold their creative behaviors in the long run,” Dr. Kyaga said.
Lamotrigine Effective Adjunct for Lithium in Bipolar Disorder
In a long-term study of bipolar patients taking lithium published in Bipolar Disorders last year, the addition of lamotrigine (or paroxetine for those who did not respond to lamotrigine) was significantly better than the addition of placebo. Patients taking lamotrigine with lithium averaged 10 months until a recurrence of a depressive or manic episode, while patients taking placebo with lithium averaged 3.5 months until an episode.
Lithium Linked to Longer Lifespan in Humans (and Worms)
An article published in the European Journal of Nutrition last year suggests that higher trace levels of lithium found naturally in drinking water in some environments are linked to longer lifespans. The authors conclude that lithium has some anti-aging properties.
We’ve written before about the cognitive benefits of small doses of lithium.
Antidepressants Prevent Suicide in Patients with Unipolar Depression
Researcher A. Kahn reported at the 51st Annual Meeting of the National Institute of Mental Health’s New Clinical Drug Evaluation Unit (NCDEU) in Boca Raton in 2011 that severely depressed and suicidal patients taking citalopram (Celexa) or a combination of citalopram and low dose lithium experienced improvements in depression and suicidal thoughts. This study was unusual because most clinical trials exclude actively suicidal patients. In the group of subjects receiving citalopram plus lithium (300 mg/day and achieving 0.5 mEq/l or higher), there were several indications of better anti-suicide effects than in those on citalopram alone. The authors concluded that with appropriate doses, antidepressants plus lithium may prospectively reduce suicidal thoughts, and that it is possible to conduct clinical trials in severely depressed and suicidal patients if adequate safety measures are included.
Surprisingly, improvement in suicidal ideation preceded improvement in depressed mood per se.
Editor’s note: The study reported here suggests that in those with high suicidal ideation scores at baseline, antidepressants with or without lithium may quickly bring about anti-suicidal effects on thoughts, desires, and behaviors. Whether these effects occur reliably in studies in other groups of patients and in younger individuals remains to be established.
These data are an interesting contrast to data on antidepressant use in those with low levels of suicidality at baseline. A number of studies have suggested that in children and adolescents who were exposed to an antidepressant, a small percentage experienced increases in suicidal ideation in the first two months of treatment compared to patients taking placebo. This led to a Federal Drug Administration (FDA) warning (directed at all patients taking antidepressants) that increases in suicidal ideation and action may occur upon starting antidepressants.
It is important to note that the warning does not refer to completed suicides; the data set that led to the FDA warning included no completed suicides. More than 70% of those with suicidal ideation do not make an attempt, and the vast majority of attempts do not result in a completed suicide.
Most of the studies that found the slight increase in suicidal ideation in some patients after beginning antidepressant treatment actively excluded acutely suicidal patients. Since the study of citalopram and lithium above used a population of severely depressed and suicidal patients and found that antidepressants improved suicidality, it appears important to consider a patient’s baseline state when considering psychiatric interventions. In another example, there is an interesting difference between the way depressed patients and non-depressed normal volunteers respond to one night’s sleep deprivation: depressed patients often show dramatic improvement, while normal volunteers tend to feel worse.
More Evidence that Antidepressants Prevent Suicide in Unipolar Depression
A new study by DeLeon published in the Journal of Clinical Psychiatry in 2011 found that during periods of life when unipolar patients were taking antidepressants (compared to times when they were not taking them) the patients experienced 20% fewer suicidal acts or completed suicides. Read more
Lithium More Effective than Valproate for Bipolar Disorder
According to two studies in 2011, lithium is more effective in treating episodes of bipolar disorder than valproate, while the drugs may be equally effective in reducing suicidality among bipolar patients.
The first study, of more than 4000 Danish patients with bipolar disorder, found that patients taking lithium had fewer hospital visits and were less likely to need new medications than those taking valproate. Patients taking lithium had fewer admissions to a hospital for any type of episode. In addition, patients taking valproate had a higher rate of switching to or adding on treatment with antidepressants, antipsychotics, or anticonvulsants than those taking lithium. The study included up to 12 years of follow-up with the patients and is the largest study with the longest period of follow-up of patients taking valproate or lithium to date. Results were published by Lars Kessing et al. in the British Journal of Psychiatry in July 2011.
In the other study, a randomized controlled trial of 100 patients with bipolar disorder who had attempted suicide at least once in the past, Maria Oquendo of Columbia University found that there were no significant differences in number of suicide attempts, hospitalizations for suicide attempts, or time to a new attempt between patients taking lithium and those taking valproate over a follow-up period of 2.5 years.
Forty-five suicide events, which included attempts, hospitalizations, and changes to medication in response to suicide plans, were experienced by 35 patients (16 who were taking lithium and 19 who were taking valproate). Eighteen suicide attempts were made by 6 patients taking lithium and 8 taking valproate. There were no suicide completions during this study, which was published in Volume 168 of the American Journal of Psychiatry in 2011.
Editor’s Note: Suicide attempts are much more common than completed suicides. It appears that the second study was not large enough or long enough to detect differences in the rate of completed suicides. Older naturalistic studies suggest that treatment results in low suicide rates and that in patients who stop treatment with lithium, the rate of suicide attempts and completion increases dramatically. This is another reason for good responders to treatment regimens that include lithium to continue taking their medications.
A Daily Small Dose Of Lithium May Prevent Progression of Mild Cognitive Impairment
A very small dose of lithium, 150 mg/day, has been reported to lessen the progression of mild cognitive impairment over a period of one year compared to placebo. In a 2011 article by Orestes Forlenza and colleagues published in the British Journal of Psychiatry, the researchers reported the findings from their prospective randomized study of lithium versus placebo in 45 patients.
Editor’s Note: While these findings must still be replicated, there are several reasons to suggest that they may be reliable and valid. Read more
A Suggested Dosing Regimen for Lithium in Children
At the 57th Annual Meeting of the American Academy of Child and Adolescent Psychiatry (AACAP) in October 2010, Bob Findling of Case Western Reserve University reported finding a 58% response rate to lithium in children with bipolar I disorder. He explored three different dosing regimens, and recommends starting children off with 300mg capsules TID (three times a day) for a total of 900 mg/day, and then increasing by a single 300mg capsule every week until there is a good effect or until side effects emerge. The most typical side effects that he saw were headache, nausea, and vomiting.
Starting at a relatively high initial dose of 900mg/day is consistent with the finding that even high doses of lithium are absorbed and transferred into the brain quite slowly. This loading approach appears to be an excellent strategy for rapidly achieving the blood levels necessary for optimal therapeutics in young children. Findling also suggests that an upper limit of blood levels as high as 1.4 mEq/l is acceptable in children because, in his experience, children often appear to need higher doses and blood levels than do adults.
Long-Term Treatment with Lithium, Valproate, or Carbamazepine: Lithium Best for Most Patients
Shannon Stepan, Eric Peselow and Nunzio Pomara from Maimonides Medical Center in Brooklyn, NY, have analyzed naturalistic observations of long-term maintenance treatment of bipolar disorder with valproic acid, lithium, and carbamazepine and found that patients on lithium went much longer before experiencing an episode of mania or depression than patients taking carbamazepine or valproate.
The team followed 225 outpatients for up to 124 months, or until they had a manic or depressive episode or dropped out of the study during a well phase. Ninety-eight patients took lithium, 78 took valproate, and 50 took carbamazepine. Fifty-two percent of the participants dropped out of the study during a well phase.
One hundred three patients (45.8%) had either a manic or depressive episode during the study. This included 36.7% of the patients taking lithium, 55% of patients taking valproate, and 50% of patients taking carbamazepine. Median time until a first episode was 45 months for the entire sample, 36 months for those patients on valproate, 42 months for those on carbamazepine, and 81 months for those on lithium. A statistical analysis known as a Cox regression model indicated that patients taking valproate had a significantly higher risk of having a manic or depressive episode than those taking lithium.
Editor’s note: These naturalistic data are highly consistent with a number of more controlled clinical studies. In particular, the BALANCE study by Geddes et al. (2010) reported that lithium was superior to valproate on most outcome measures in a two-year randomized study, and that the combination of lithium and valproate was significantly better than valproate alone. Read more
Dopamine D2 and D3 Agonist Pramipexole May Enhance Cognitive Function in Bipolar I Disorder
Anil Malhotra from the Zucker Hillside Hospital found that pramipexole (Mirapex), a dopamine D2 and D3 agonist used in the treatment of Parkinson’s disease, improved measures of processing speed and working memory in euthymic bipolar patients (whose average age was 42) when compared with placebo in an adjunctive clinical trial.
Editor’s Note: Bipolar patients in a euthymic phase have consistently been shown to have some degree of cognitive dysfunction that is typically correlated with the number of prior depressive and/or manic episodes they have experienced. This is one of the first studies to directly target this cognitive dysfunction with a pharmacotherapeutic agent.
Pramipexole may be of additional value among depressed patients, because in two small, placebo-controlled studies, one led by Carlos Zarate at the National Institute of Mental Health and one led by Joseph F. Goldberg in New York, pramipexole has been shown to exert acute antidepressant effects in bipolar patients in the depressive phase of the illness. The new data from Malhotra raise the possibility that there could be a two-for-one benefit when pramipexole is used in the depressive phase of bipolar illness—improvement in both depression and cognition.
