Studies of rodents with depression-like behaviors revealed that the combination of low (sub-therapeutic) doses of lithium and infusions of ketamine produced antidepressant-like effects. Researchers believed this might mean that in humans, lithium might have a unique effect potentiating the effects of ketamine.
In a small study by Mark J. Niciu presented at the 2015 meeting of the Society for Biological Psychiatry, patients with bipolar depression taking lithium or valproate mood stabilizers were given ketamine infusions or control infusions. In the 23 patients taking lithium and the 13 taking valproate, ketamine’s antidepressant effects were significantly better than placebo, but there was no difference between lithium and valproate with regard to these antidepressant effects. These preliminary data in a small number of subjects do not support the proposition that lithium augments the effects of ketamine in depression.
Lithium inhibits the enzyme glycogen synthase kinase 3, which has been implicated in dementia. To study whether lithium may prevent cognitive decline, researchers led by Tobias Gerhard looked at the medication histories of patients with bipolar disorder who were 50 years of age or older. In their article published in the British Journal of Psychiatry, those patients who had taken lithium 301–365 days out of the previous year had substantially lower risk of dementia than those who had not taken lithium during that time. Patients who had 300 or fewer days of lithium use did not have a significant reduction in dementia risk, nor did patients who were prescribed anticonvulsant drugs.
Editor’s Note: These data are consistent with those of Lars Kessing and colleagues, which suggest that patients in Denmark who renewed their lithium prescriptions were less likely to receive a diagnosis of dementia in old age.
In 2011, Orestes V. Forlenza and colleagues also reported in the British Journal of Psychiatry that compared to placebo, a very small dose of lithium, 150 mg/day, slowed the progression of mild cognitive impairment over one year.
Long-term lithium use has long been associated with decreased renal function. But some Swedish researchers noticed that most long-term studies of patients with renal failure had begun in the 1960s and 1970s. In the 1980s, when it became clear that lithium could reduce renal function, doctors began to institute new safety measures for lithium users, including monitoring of blood levels of the drug and of creatinine, a substance that is excreted by the kidneys as part of normal muscle metabolism. So the researchers undertook a new study to examine whether the protocols instituted in the 1980s had reduced the renal risks of long-term lithium use. Unfortunately, they found that some reduced renal function is still common among people who use lithium for longer than 10 years, and this risk does not necessarily decrease when patients stop taking lithium.
The researchers, led by Harald Aiff, published the study in the Journal of Psychopharmacology in 2015. They identified 4,879 patients who had been prescribed lithium, and narrowed this list down to 630 adult patients who had taken lithium for at least 10 cumulative years, who had normal levels of creatinine when they began taking lithium, and on whom good data existed. About one-third of these patients had evidence of chronic renal impairment, and in 5% of these the impairment was severe or very severe.
Aiff and colleagues’ findings show that lithium treatment requires careful monitoring, especially over the long term. Patients must consider the risk/benefit ratio of lithium treatment. Since prevention of mood episodes can preserve an average ten years of life expectancy, and lithium has the best data for efficacy in preventing manic and depressive episodes, patients must weigh the risks of insufficiently treated bipolar illness against the possibility for long-term decreases in kidney function.
Studies in Japan, Austria, and Texas have reported that trace amounts of lithium in drinking water are associated with lower suicide rates. A new study seeks to clarify these findings by removing any statistical factors other than lithium levels that could produce these results.
The study, published in the Journal of Clinical Psychiatry, collected 434 lithium samples in drinking water over three years, and compared these with suicide rates in the population of 274 municipalities of Kyushi Island in Japan.
The researchers, led by Nobuyoshi Ishii, then controlled for size of population, proportion of elderly people, proportion of one-person households, proportion of people with a college education or more, proportion of people engaging in primary industry, overall unemployment rates, annual marriage rates, annual mean temperature, and annual savings in per person in Japan’s popular postal bank. In places with slightly higher trace levels of lithium in drinking water, there was a lower rate of suicides in men. Suicide rates for women and overall were not significantly associated with lithium levels.
Telomeres are repeated DNA sequences that sit at the end of chromosomes and protect them during cell replication. Telomeres get shorter with aging and with stressors or psychiatric illnesses. Researcher Alexandre Mathe and colleagues recently found that in a line of rats bred to be more susceptible to stress and depression-like behavior, hippocampal telomeres were shorter than in normal rats or rats bred to be less susceptible. The susceptible rats also had lower levels of enzymes that maintain telomere length. Both telomerase activity and Tert (telomerase reverse transcriptase) expression were reduced in the susceptible rat compared to the other rats. However, lithium reversed the low levels of telomerase activity and Tert expression.
Editor’s Note: Lithium increases hippocampal volume in people, and also increases human telomerase. Researcher Lina Martinsson reported in 2013 that lithium increases telomere length in white cells. Now lithium has increased hippocampal telomerase in a rat model of depression. Short telomeres are associated with aging and increased vulnerability to a wide range of medical and psychiatric disorders. Since people with bipolar disorder are prone to memory problems, medical problems, and short telomeres, they might want to talk to their physician about including lithium in their treatment regimen, if they are not already taking it.
While it can sometimes take weeks for the effects of antidepressant treatments to appear, intravenous ketamine can produce antidepressant effects in as little as two hours. However, ketamine’s effects fade after three to five days. New animal research by Chi-Tso Chiu et al. explores whether adding lithium to ketamine treatment can produce more sustained antidepressant effects.
Mice who are restrained by being placed in a tube for several hours (chronic restraint stress) exhibit a behavioral and neurochemical profile that resembles human depression. When Chiu and colleagues pretreated these stressed mice with sub-therapeutic doses of lithium (600 mg/L) in their drinking water for several weeks, a sub-therapeutic dose of ketamine (2.5 mg/kg of body weight) was enough to produce robust antidepressant effects in the mice, while neither drug alone was effective at these doses.
The combination of ketamine and lithium also restored the density of spines on the dendrites of neurons in the medial prefrontal cortex. Post-treatment with lithium (1200 mg/L) for several weeks was also successful in extending the effects of a single (50 mg/kg) ketamine injection.
Both lithium and ketamine affect the intracellular signaling pathway mTOR. Ketamine activates the pathway, increasing levels of synaptic proteins and dendritic spine density. It also increases brain-derived neurotrophic factor (BDNF) and the BDNF receptor TrkB. BDNF is important for learning and memory.
When lithium was added to the treatment of the mice with ketamine, the mTOR and BNDF pathways were further activated. Lithium also inhibits the receptor GSK-3, supporting ketamine’s rapid-acting antidepressant effects.
Ketamine treatment can produce oxidative stress, in which toxic free radicals can endanger cells, and the addition of low doses of lithium also completely prevented this neurochemical side effect.
Chiu and colleagues hope that the findings of this study in mice can eventually be applied to research in humans in the hopes of finding a clinical option that would sustain the rapid-onset antidepressant effects of ketamine for the long term.
There is a large body of research showing that lithium is better than placebo and a variety of comparison drugs at preventing manic episodes in people with bipolar disorder. It has been less clear whether lithium is as effective in preventing depressions in bipolar patients. In a 2014 meta-analysis in the International Journal of Bipolar Disorders, Emanuel Severus and colleagues confirmed that lithium was more effective than placebo at preventing mood episodes overall and manic episodes. In a fixed effect statistical analysis, lithium was also better at preventing depressive episodes.
The portion of the meta-analysis comparing lithium to placebo included seven randomized controlled trials that included a total of 1,580 patients. Lithium was more likely than placebo to lead to patients dropping out of a study for reasons other than a mood episode, but patients who received lithium were more likely to complete their clinical trials.
Another part of the meta-analysis compared lithium to anticonvulsant drugs. Seven trials were included totaling 1,305 patients. Lithium was better than anticonvulsants at preventing manic episodes, but equally effective at preventing mood episodes overall and depressive episodes specifically. There was also no difference in patients dropping out of the trials or completing the trials.
The researchers concluded that lithium remains the most valuable treatment option for bipolar disorder, because no other drug has such consistent efficacy in preventing manias and depressions and mood episodes in general.
At the 2014 meeting of the American Academy of Child and Adolescent Psychiatry, researcher Adelaine Robb reported that in 81 children with mania (aged 7-17), lithium was superior to placebo in reducing the severity of mania measured on the Young Mania Rating Scale. There had been some debate about the efficacy of lithium in young children with mania, but this study clearly indicates lithium’s effectiveness. The drug is approved by the Federal Drug Administration (FDA) for use in patients with bipolar disorder aged 12 and up.
Another researcher, Vivian Kafrantaris, found that in children who averaged 14.5 years of age, lithium increased the volume of the corpus callosum, a bundle of neural fibers that connects the brain’s right and left hemispheres. Lithium also normalized white matter integrity in other neural fiber tracts—the cingulum bundle and the superior longitudinal fasciculus. The authors concluded that lithium may “facilitate microstructural remodeling of white matter tracts involved in emotional regulation.”
Editor’s Note: There is much research showing that in adults, lithium has positive effects on the brain, including increases in hippocampal and cortical grey matter volume. Now it appears that lithium can improve white matter integrity in the developing brain as well.
Lithium Plus An Atypical Antipsychotic Was More Effective Than Valproate Plus An Atypical Antipsychotic In One Study, But Not Another
Evaristo Nieto et al. of Spain presented a poster about the naturalistic study of the efficacy of acute treatment of manic inpatients with lithium and valproate at the 2014 meeting of the International College of Neuropsychopharmacology. In the lithium group, all patients were treated with lithium and oral antipsychotics (N=85). In the valproate group, all were treated with valproate and oral antipsychotics (N=92). Outcome was measured using scores on scales for mania and for general functioning (the YMRS and the CGI-S). The atypical antipsychotic was typically olanzepine or risperidone.
Nieto et al. found that the mean change in CGI scores from baseline to the day of discharge was significantly higher in the lithium group (-2.84 versus -2.6), and concluded that, “Although it is used in more severe cases, treatment of manic inpatients with lithium associated with antipsychotics is more effective than treatment with valproate associated with antipsychotics.”
However, W.M. Bank et al. came to the opposite conclusion in a Korean study. Bank et al. “compared the 1-year rehospitalization rates of first-episode bipolar manic patients?who were discharged while being treated with lithium or valproate in combination with an?atypical antipsychotic….The rehospitalization rate was 17.3% during the 1-year follow-up period.”
Bank et al. found significantly higher rates of rehospitalization in the lithium (23.1%) compared to the?valproate (13.3%) group using the Kaplan-Meier formula for estimations.
In a recent study comparing the efficacy of lithium and the second-generation antipsychotic quetiapine, the drugs had remarkably similar results. Researcher Andrew Nierenberg et al. presented the results at the 2014 meeting of the American Society of Clinical Psychopharmacology. In the 6-month study called CHOICE (Clinical Health Outcome Initiative Comparative Effectiveness), 482 patients received either lithium or quetiapine in addition to other medications in a manner consistent with clinical practice. For the purposes of the study, those receiving lithium could not receive quetiapine or another antipsychotic, and those receiving quetiapine could not receive lithium or another antipsychotic, but both groups could receive other types of adjunctive medications.
By the end of the 6-month study period, most patients had improved substantially, but only about a quarter of each group became truly well. The researchers suggest that patients may need a longer period of treatment or other interventions such as psychotherapy or combination treatment. Clinicians were told to use the maximum dose of lithium or quetiapine that each patient could tolerate. Mean maximum doses were 1007.5mg of lithium and 344.9mg of quetiapine.
One surprise for the researchers was that 24% of lithium patients and 27% of quetiapine patients required no other medications and improved on monotherapy.
While results were very similar for two drugs, lithium produced slightly greater side effects and produced slightly better results in patients with anxiety. This may have been due to those patients also receiving benzodiazepines, and the researchers are analyzing data to see whether the patients with anxiety did indeed receive this kind of adjunctive treatment. Quetiapine was slightly better in patients who had more manic symptoms.
In another surprise finding, patients with bipolar II disorder fared better overall than patients with bipolar I disorder. Patients with higher suicide risk did worse than those with lower suicide risk.