Lithium therapy is used for affective disorders and treatment-resistant schizophrenia. Lithium causes mood stabilization and is the only known drug that has been shown to have a suicide-preventive effect.
What is lithium therapy?
Lithium therapy, used in psychiatry, involves administering lithium to stabilize mood. The use of lithium as a drug in the context of psychiatry has occurred since the early 20th century. Lithium therapy is the only therapy that is suicide-preventive in affective disorders, such as depression and bipolar disorder. Lithium is not administered by itself, but in the form of its salts. Lithium therapy is considered well researched and safe. In the correct dosage, the salts of lithium are well tolerated and effective. However, the exact mechanism of action of lithium therapy is not known.
Function, effect, and goals
Lithium therapy is used for recurrent depression, recurrent episodes of mania and depression in bipolar disorder, and treatment-resistant schizophrenia. Furthermore, lithium is also used as a second-line agent for the preventive treatment of cluster headache. In Europe, however, the administration of antiepileptic drugs to stabilize mood is preferred in psychiatry. In the United States, however, lithium therapy is much more widely used for the above indications. Lithium was first described as a psychiatric drug in 1949 by the Australian psychiatrist John F. Cade. He discovered the antimanic effect of the substance rather accidentally in an animal experiment and subsequently administered the substance to his manic patients, who also experienced an effect. Cade was instrumental in the further development of lithium therapy until his death. Despite good research, the exact mechanism of action of the substance is still not known today. It has only been proven that the salts of lithium have a modifying effect on the functions of the body at very many different points. It is generally assumed that the effectiveness of lithium therapy in the above-mentioned psychiatric disorders is based on the fact that during a manic episode the lithium lowers an excess of noradrenaline, whereas during depressive episodes the production of serotonin is stimulated. Lithium therapy, if carried out over a longer period of time, can thus lead to a balancing of the patient’s mood. The assumption seems conclusive in that the effects of lithium would be logically explained by its regulating and balancing effects. However, conclusive proof that the effect actually results from the aforementioned processes has not yet been provided. The therapeutic range, i.e. the range between the effective and the harmful dose, is small for lithium. For this reason, self-administration of lithium therapy is clearly not recommended. Furthermore, the concentration of lithium in the blood must be monitored regularly during therapy to rule out overdose. Absolute contraindications exist in acute myocardial infarction, pronounced hyponatremia (insufficient sodium concentration in the blood), severe renal insufficiency, acute renal failure and severe heart failure. In addition, pregnancy and Addison’s disease (adrenal insufficiency) are relative contraindications. There is some evidence regarding the implementation of lithium therapy during pregnancy. Since after a lithium therapy during pregnancy malformations in the newborns occurred frequently, the salts of the lithium were considered teratogenic (fruit-damaging) and advised against an application in pregnancy, in order not to endanger the unborn child. Today, it has become accepted that lithium therapy during pregnancy, while certainly risky, should not be ruled out in every case. Even the diseases that can be treated well with lithium therapy can be dangerous for the unborn child. The risk of malformations of the newborn is demonstrably increased five to ten times after lithium therapy of the pregnant woman.The guideline today is a very strict indication; a desired consistently low serum concentration of lithium, which requires dose adjustment; a reduction in dose during the week of delivery; monitoring of the newborn for symptoms of intoxication; and, if therapy is given in the first trimester of pregnancy, ultrasound diagnosis and echocardiography of the fetus. Lithium is the only agent that has been shown to reduce the risk of suicide in affective disorders. In addition, it has been demonstrated by a group from the University of Vienna that the suicide rate in regions with a high concentration of lithium in drinking water is lower than in regions with a low concentration of the substance in drinking water.
Risks, side effects and hazards
Lithium therapy, like any other drug therapy, is associated with certain risks. Thus, some more or less serious side effects may occur in the course of therapy. Weight gain, circulatory disturbances, tremor occurring especially in the hands, nausea, vomiting, changes in the blood count (leukocytosis), fatigue, increased thirst and urination, diarrhea, and hypothyroidism are typical side effects of lithium therapy. If the therapeutic dose is exceeded, drowsiness, convulsions, and coma may occur. Since the therapeutic range of the drug is small, regular monitoring of serum levels is recommended to reduce the risk of occurrence of such complications. Prolonged use, even in therapeutic doses, may lead to diabetes insipidus, acidosis (hyperacidity of the blood) and so-called lithium nephropathy with impaired renal function. Ibuprofen, diclofenac and other NSAIDs as well as ACE inhibitors interact with lithium in that they inhibit the excretion of the substance. Lithium is not addictive. Nevertheless, tapering is necessary to avoid side effects of discontinuation.
