A cause of Bipolar Disorder is discovered thanks to lithium

Although bipolar disorder affects between 1% and 3% of the population, the great variability of its possible causes means that its nature remains relatively unknown. Something similar 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 journal Proceedings of the National Academy of Sciences has provided fundamental keys on the mechanism of action of lithium and the cause of cases of bipolar disorder that improve with this drug. Specifically, they have detected alterations in the CRMP2 protein.

• Related article: "Bipolar Disorder: 10 characteristics and curiosities that you did not know"

Characteristics of Bipolar Disorder

Bipolar disorder is characterized by the occurrence of periods between weeks and months in which the state of mood is pathologically low (depression), along with others in which energy levels are increased significantly and a feeling of emotional euphoria (mania) predominates.

Both manic and depressive episodes significantly interfere with a person's normal functioning; in fact, this disorder is the sixth most frequent cause of disability in the world population.

Specifically, the diagnosis of bipolar disorder is associated with a marked increased risk of suicide and self-harm. This is one of the reasons why it is customary to treat with powerful drugs; if these do not work, you may even apply a Electroconvulsive therapy.

• You may be interested in: "Types of Bipolar Disorder and its characteristics"

The causes of this disorder

The onset of bipolar disorder has been linked to a large number of different causes. It is believed that genetic inheritance explains 70% of the risk of developing this disorder, approximately.

However, the exact causative genes are not clear, since they appear to vary from case to case; the dominant hypothesis defends that there are multiple genes involved.

In addition, the finding of structural and functional alterations in regions such as the lateral ventricles, the basal ganglia and the amygdala suggests that anatomical and physiological factors also play a relevant causal role.

On the other hand, not all people with a biological predisposition to bipolar disorder develop it. For it to happen psychosocial stress is often required, especially during the early stages of life; The fact that 30-50% of the affected people report having suffered abuse or trauma in childhood is striking.

What is lithium?

Lithium is a chemical element of the family of metals. It is the solid element, and therefore also the 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 wave cyclical depression.

Among other effects, lithium decreases the risk of suicide in people with these disorders. Although it is the drug of choice to treat bipolar disorder, lithium is only effective in about a third of those affected.

Furthermore, since the therapeutic dose is very close to the toxic dose, lithium carries risks and causes secondary symptoms and reactions. relevant adverse events, such as emotional numbing, weight gain, muscle tremors, nausea, or the onset of diabetes insipidus; and hypothyroidism.

Lithium began to be used as a psychotropic drug about 60 years ago. Yes ok its effectiveness in treating the symptoms of bipolar disorder (as we have seen, in a third of the cases) has been widely demonstrated in this time, until very recently the cause of these effects was not known, that is, its mechanism of action.

• Related article: "Types of psychoactive drugs: uses and side effects"

The mechanism of action of lithium

The research team headed by Evan Snyder analyzed the brain cells of people with bipolar disorder distinguishing between those that responded well to lithium and those that did not. Specifically, they used artificial stem cells to study the pathway of lithium once it has been introduced into the body.

Snyder and his colleagues found that in cases of bipolar disorder that benefit from lithium treatment, the CRMP2 protein, which regulates the central nervous system. It seems that CRMP2 activity is altered, since 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 reinforces the theory dominant that states that it is a polygenic disorder (that is, not determined by a single gene).

The discovery of the mechanism of action of lithium may favor 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 case should be considered a determining aspect in the choice of the most appropriate pharmacological treatment for the person.