Relationship of Neurotransmitters to the Symptoms of Major Depressive Disorder

Neurotransmitters are chemical messengers in our brain that help regulate our mood, control our appetite, regulate thoughts, sleep and concentration among other things. Major depressive disorder and other mental health disorders are usually the result of an imbalance of these neurotransmitters in the brain.

Serotonin and GABA

• Serotonin and GABA are two main neurotransmitters in the brain that help regulate mood. GABA helps regulate other neurotransmitters like serotonin, dopamine and norepinephrine. A shortage of these two chemical messengers in the brain are partly responsible for the depressed mood, increased anxiety symptoms, sleeping problems and lack of energy seen in major depressive disorder and other mental health problems.

Dopamine

• Dopamine is the major neurotransmitter in the brain responsible for motivation and drive. An imbalance of dopamine supply in the brain is often seen in major depressive disorder and is usually responsible for a depressed individual's lack of energy, motivation, poor concentration and even mood swings.

Norepinephrine

• Norepinephrine is also known as adrenaline and has mainly excitatory effects on the brain and body. A shortage of this neurotransmitter in the brain could mean a lack of energy or focus, but abnormally high levels can lead to increased anxiety and stress levels as well as increased blood pressure.

Causes

• There is no single "cause" for neurotransmitter imbalances in the brain as they relate to major depressive disorder and other mental health disorders as there are usually a variety of factors responsible. Some common ones include genetic factors, long-term drug or alcohol use, hormonal changes, poor diet and even trauma at birth or shortly after.

Medications

• Anti-depressant and anti-anxiety medications are used to even out the imbalance of neurotransmitters in the brain. Selective Serotonin Reuptake Inhibitors (SSRIs) and Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs) are two common classes of prescription drugs used to treat major depressive disorder and other mental illnesses. These drugs effectively increase the availability of these neurotransmitters to the brain, thereby elevating mood and other symptoms of the disorder.