Again bipolar disorder affects between 1% and 3% of the populationThe great variability of its possible causes makes its nature still relatively unknown. Something similar has happened until recently with lithium, the drug of choice in the treatment of this disorder, which has been used for decades without its mechanism of action being known.
A study by Evan Snyder, Brian Tobe and others recently published in the Proceedings of the National Academy of Sciences provided key insights into the mechanism of action of lithium and the cause of bipolar disorder that gets better with this drug. More precisely, they detected alterations in the CRMP2 protein.
Characteristics of bipolar disorder
Bipolar disorder is characterized by the appearance of periods between weeks and months in which the mood is pathologically low (depression), as well as others in which energy levels rise significantly and a feeling of emotional euphoria (mania) predominates.
Episodes of mania and episodes of depression significantly interfere with a person’s normal functioning; in fact, this disorder is the sixth most common cause of disability in the world population.
More specifically, the diagnosis of bipolar disorder is associated with a staining increased risk of suicide and self-harm. This is one of the reasons it is usually treated with strong drugs; if these do not work, electroconvulsive therapy may even be applied.
The causes of this disorder
The onset of bipolar disorder has been linked to a number of different causes. One thinks that genetic inheritance represents 70% of the risk of developing this disorder, About.
However, the specific causal genes are unclear, as they seem to vary from case to case; the dominant hypothesis holds that several genes are involved.
Additionally, the discovery of structural and functional alterations in regions such as the lateral ventricles, basal ganglia, and amygdala suggests that anatomical and physiological factors also play relevant causal roles.
In contrast, not all people with a biological predisposition to bipolar disorder develop it. For it to happen it is often necessary for psychosocial stress to occur, Especially during the early stages of life; It should be noted that 30 to 50% of those affected report having suffered abuse or trauma in their childhood.
What is lithium?
Lithium is a chemical element of the family of metals. It is the solid element, and therefore also metal, the lightest of all. At the pharmacological level, lithium salts are used to regulate mood in the treatment of bipolar disorder and other similar psychological problems, such as schizoaffective disorder or cyclical depression.
Among other effects, lithium decreases the risk of suicide in people with these disorders. Although it is the drug of choice for treating bipolar disorder, lithium is only effective in about a third of those affected.
In addition, since the therapeutic dose is very close to the toxic dose, lithium carries risks and causes relevant side symptoms and adverse effects, such as emotional numbness, weight gain, muscle tremors, nausea or the onset of diabetes insipidus and hypothyroidism.
Lithium began to be used as a psychotropic drug around 60 years ago. even if its effectiveness in treating the symptoms of bipolar disorder (As we have seen, in a third of cases) it was widely demonstrated at this time, until very recently the cause of these effects was not known, i.e. its mechanism of action.
The mechanism of action of lithium
The research team led by Evan Snyder analyzed the brain cells of people with bipolar disorder, distinguishing between those who responded well to lithium and those who did not. Specifically, they used artificial stem cells to study the trajectory of lithium once it was introduced into the body.
Snyder and his colleagues have found that in cases of bipolar disorder that benefit from lithium therapy is involved CRMP2 protein, which regulates the central nervous system. In the opinion of CRMP2, the activity is altered because it is much lower in these patients than in those who do not respond adequately to lithium.
This finding indicates that there are different variants of bipolar disorder, which strengthens the dominant theory that it is a polygenic disorder (i.e., not determined by a single gene).
The discovery of lithium’s mechanism of action may promote the development of more effective drugs and with fewer side effects, as it allows research efforts to be focused on the most relevant biological processes.
Likewise, the study by Snyder’s team suggests that identifying the causes of bipolar disorder in each particular case should be considered a determining factor in choosing the most appropriate pharmacological treatment for the person.