Mood stabilizer
A mood stabilizer is a psychiatric medication used to treat mood disorders characterized by intense and sustained mood shifts, such as bipolar disorder and the bipolar type of schizoaffective disorder. Uses. Mood stabilizers are best known for the treatment of bipolar disorder, preventing mood shifts to mania (or hypomania) and depression. Mood stabilizers are also used in schizoaffective disorder when it is the bipolar type. Examples. The term "mood stabilizer" does not describe a mechanism, but rather an effect. More precise terminology based on pharmacology is used to further classify these agents. Drugs commonly classed as mood stabilizers  include: Anticonvulsants. Many agents described as "mood stabilizers" are also categorized as anticonvulsants. The term "anticonvulsant mood stabilizers" is sometimes used to describe these as a class. Although this group is also defined by effect rather than mechanism, there is at least a preliminary understanding of the mechanism of most of the anticonvulsants used in the treatment of mood disorders. There is insufficient evidence to support the use of various other anticonvulsants, such as gabapentin and topiramate, as mood stabilizers. Combination therapy. In routine practice, monotherapy is often not sufficiently effective for acute and/or maintenance therapy and thus most patients  are given combination therapies. Combination therapy (atypical antipsychotic with lithium or valproate) shows better efficacy over monotherapy in the manic phase in terms of efficacy and prevention of relapse. However, side effects are more frequent and discontinuation rates due to adverse events are higher with combination therapy than with monotherapy. Relationship to antidepressants. Most mood stabilizers are primarily antimanic agents, meaning that they are effective at treating mania and mood cycling and shifting, but are not effective at treating acute depression. The principal exceptions to that rule, because they treat both manic and depressive symptoms, are lamotrigine, lithium carbonate, olanzapine  and quetiapine. Nevertheless, antidepressants are still often prescribed in addition to mood stabilizers during depressive phases. This brings some risks, however, as antidepressants can induce mania, psychosis, and other disturbing problems in people with bipolar disorder—in particular, when taken alone. The risk of antidepressant-induced mania when given to patients concomitantly on antimanic agents is not known for certain but may still exist. The majority of antidepressants appear ineffective in treating bipolar depression. Antidepressants cause several risks when given to bipolar patients. They are ineffective in treating acute bipolar depression, preventing relapse, and can cause rapid cycling. Studies have  shown that antidepressants have no benefit versus a placebo or other treatment. Antidepressants can also lead to a higher rate of non-lethal suicidal behavior. Relapse can also be related to treatment with antidepressants. This is less likely to occur if a mood stabilizer is combined with an antidepressant, rather than an antidepressant being used alone. Evidence from previous studies shows that rapid cycling is linked to use of antidepressants. Rapid cycling is defined as the presence of four or more mood episodes within a year's time. Evidence suggests that rapid cycling and mixed symptoms have become more common  since antidepressant medication has come into widespread use. There is a need for caution when treating bipolar patients with antidepressant medication due to the risks that they pose. Use of mood stabilizers and anticonvulsants such as lamotrigine, carbamazapine, valproate and others may lead to chronic folate deficiency, potentiating depression. Also, "Folate deficiency may increase the risk of depression and reduce the action of antidepressants." L-methylfolate (also formally known as 5-MTHF or levomefolic acid), a centrally acting trimonoamine modulator, boosts the synthesis of three CNS neurotransmitters: dopamine, norepinephrine and serotonin. Mood stabilizers and anticonvulsants may interfere with folic acid  absorption and L-methylfolate formation. Augmentation with the medical food L-methylfolate may improve antidepressant effects of these medicines, including lithium and antidepressants themselves, by boosting the synthesis of antidepressant neurotransmitters. However, the U.S. National Institutes of Health issued a warning caution about the use of L-methylfolate for patients with bipolar disease. Pharmacodynamics. The precise mechanism of action of lithium is still unknown, and it is suspected that it acts at various points of the neuron between the nucleus and the synapse. Lithium is known to inhibit the enzyme GSK-3B. This improves the functioning of the circadian clock—which  is thought to be often malfunctioning in people with bipolar disorder—and positively modulates gene transcription of brain-derived neurotrophic factor (BDNF). The resulting increase in neural plasticity may be central to lithium's therapeutic effects. How lithium works in the human body is not completely understood, but its benefits are most likely related to its effects on electrolytes such as potassium, sodium, calcium and magnesium. All of the anticonvulsants routinely used to treat bipolar disorder are blockers of voltage-gated sodium channels, affecting the brain's glutamate system. For valproic acid, carbamazepine and oxcarbazepine, however, their mood-stabilizing effects  may be more related to effects on the GABAergic system. Lamotrigine is known to decrease the patient's cortisol response to stress. One possible downstream target of several mood stabilizers such as lithium, valproate, and carbamazepine is the arachidonic acid cascade.