Introduction:
Mental health issues are very common in today's world. Due to changes in our habits and in our day-to-day activities, a large number of people are suffering from such conditions. Every one out of eight persons in the world suffers from such complications. Two of the most common drugs used in the treatment of such cases are mood stabilizers and antidepressants.
What Are Mood Stabilizers?
Mood stabilizers are a group of drugs that are used to treat bipolar disorder (a major mental illness characterized by major or rapid shifts in emotions and mental conditions). These drugs are used to treat manic and depressive episodes associated with bipolar disorder. These drugs can also be used as prophylactic drugs or in the treatment of depression. Mood stabilizers can be divided into two generations. These are the first and second mood stabilizers. The first generation of mood stabilizers, including Lithium, Valproates, and Carbamazepine, was introduced during the 1960s and 1970s. In the 1990s, the second generation of mood stabilizers was introduced, which includes Clozapine, Olanzapine, Quetiapine, and Lamotrigine. Additionally, there are certain drugs used as adjuvant medications for enhancing mood. These drugs, referred to as insufficient mood stabilizers, include Asenapine and Topiramate.
-
Lithium: G-proteins are the molecules on the cell surface that help signal transportation. G-proteins, along with neurotransmitters, aid in the process of cellular signal transfer, cell growth, and differentiation. In patients with bipolar disorder, lithium is used to stimulate basal activity and inhibit stimulated adenylate cyclase. It also potentially results from the stabilization of the inactive G protein by lithium. Lithium is also responsible for the downregulation of polyphosphoinositide signaling by acting as an uncompetitive inhibitor of inositol monophosphatase and inositol polyphosphate 1-phosphatase. Lithium is the strongest drug used in bipolar disorder monotherapy for more than fifty years.
-
Valproate: Valproate or valproic acid can be used for the treatment or management of acute mania and mixed episodes. The potent compound belonging to this drug is Divalproex sodium. This drug can also be used as part of combination therapy or can be used in patients suffering from complex, partial, and simple seizures. This drug is responsible for the obstruction of sodium into neurons. This causes decreased firing potential and excitability of neurons. Valproic acid also has an inhibitory effect on neurotransmitters like GABA (.gamma-aminobutyric acid). The degradation of GABA facilitates this action. Valproate also modulates various calcium channels responsible for neuronal signaling, neurotransmitter release, gene expression, and cellular survival.
-
Carbamazepine: Carbamazepine is used in patients suffering from bipolar disorder I. This can also be used as a combination drug in patients suffering from mixed episodes of bipolar disorder. This drug acts on the sodium channels and causes a decrease in neurotransmission and action potential of the neurons. This drug also acts on the G-protein-coupled receptors and is responsible for the modulation of neurotransmission. This drug also has inhibitory effects on the action of the enzyme adenylyl cyclase, which attenuates cyclic AMP-mediated signaling pathways.
-
Clozapine: This is an antipsychotic drug that is used mainly for the treatment of schizophrenia. In bipolar disorder, this drug is used to prevent recurrences in severe and drug-resistant cases. It can also be used along with lithium as a combination drug.
-
Lamotrigine: This is an FDA (Food and Drug Administration) approved drug that is used in cases of bipolar disorder I or the maintenance phase of the therapy. This drug is effective in fighting cases of recurrent depression and rapid-cycling bipolar depression. This drug acts on the sodium channels and regulates presynaptic glutamate and aspartate release.
What Are Antidepressants?
Depression is a mental disorder characterized by major episodes of sadness and unhappiness. In this condition, people persistently feel demotivated and complain of irregular sleep patterns and eating habits. Also, other symptoms of depression are anxiety, excessive stress, and mood swings are seen. Antidepressants are the drugs that are used to treat such conditions. Different types of antidepressants are;
-
Selective Serotonin Reuptake Inhibitors (SSRIs): These drugs act on presynaptic terminals and prevent the reuptake of serotonin. As a result, such drugs prolong serotonergic neurotransmission. Also, prolonged use of these drugs is associated with increased neural signaling. This is achieved by increasing cyclic AMP signaling and increasing expression of brain-derived neurotrophic factor (a factor responsible for neural growth and differentiation). The drugs belonging to this group are; Sertraline, Fluvoxamine, Fluoxetine, and Paroxetine.
-
Serotonin or Norepinephrine Reuptake Inhibitors (SNRIs): These drugs prevent the reuptake of serotonin and norepinephrine. However, the effect of inhibition of both of these neurotransmitters may vary according to the drugs. Different drugs belonging to this group are Venlafaxine, Desvenlafaxine, Duloxetine, and Milnacipran. Apart from Milnacipran, the other three drugs are known to inhibit serotonin predominantly. However, Milnacipran is known as a balanced reuptake inhibitor among SNRIs. Another drug, Levomilnacipran, is known for predominantly inhibiting norepinephrine uptake.
- NMDA Antagonists: These drugs are known for preventing the action of N-Methyl-D-aspartate receptors (NMDAR). These drugs are known for dysregulating glutamatergic neurotransmission by preventing its binding to the NMDA receptors. These drugs are also known for altering the action of the neurotransmitters like GABA. Esketamine and Dextromethorphan are the drugs belonging to this group. Dextromethorphan is known for its unique action over opioid receptors, which causes hyperpolarization of nerve cells. That is why it is often combined with another antidepressant, Bupropion, to prevent reuptake of dopamine and norepinephrine.
- Monoamine Oxidase Inhibitors (MAOIs): These are the first introduced antidepressants. These drugs act on the monoamine oxidase enzyme, which is responsible for breaking down neurotransmitters like serotonin, norepinephrine, and dopamine. The drugs belonging to this group are Selegiline, Moclobemide, Tranylcypromine, and Isocarboxazid.
What Are the Indications of Mood Stabilizers and Antidepressants?
-
Antidepressants are mainly used for the treatment of various depressions. SSRIs are used as the first line of drugs in the treatment of depression. Esketamine is used for treatment-resistant depressive disorders. For the treatment of major depressive disorders, a fixed-dose combination of Dextromethorphan-Bupropion is used. These drugs are also used in various psychological disorders like obsessive-compulsive disorder (a mental disorder with uncontrollable repetitive thoughts), social phobia, melancholia (psychomotor disorder with agitation or retardation), psychotic depression (depression with hallucination), panic disorder, generalized anxiety disorder (GAD), and post-traumatic stress disorder (PTSD, stress due to previous traumatic episodes).
-
Mood stabilizers are primarily used in bipolar disorders or the treatment of manic episodes. Valproate or valproic acid can be used as an anti-epileptic drug for the treatment of seizures.
However, depending on clinical situations both of these drugs can be used together or in combination as a part of adjuvant therapy.
Conclusions:
Mood stabilizers and antidepressants are both used for the treatment of psychological disorders. While mood stabilizers are primarily used for bipolar disorder, antidepressants are used in cases of depression. Both drugs have unique mechanisms of action, which are essential for their clinical applications.
