According to Schulz et al. (2015), depression presents as a symptom of most psychiatric illnesses including Major depressive disorder, bipolar disorder, and schizophrenia. Depression can also be a presenting symptom of several neurodegenerative disorders, including Alzheimer’s disease, dementia with Lewy bodies, frontotemporal dementia, and Parkinson’s disease. Depression may lead to cognitive impairment and is a risk factor for dementia.
Depression is one of the leading causes of disability worldwide. In the United States alone, the 1-year prevalence of Major depressive disorder is 2.7% to 10.3%. The pathophysiology of depression is not clear. However, it is thought to be connected with the neurotransmitter serotonin and other neurotransmitters like dopamine. There is an explanation of how these neurotransmitters cause depression. Neurotransmitters are known to attach themselves to the end of brain receptors as a means of communication. However, in depressed individuals, due to unknown reasons, neurotransmitters do not stay with the receptors long enough, which can disrupt the balance of communication and various aspects of the brain resulting in the symptoms associated with the disorder.
The major signs and symptoms, as well as complaints presented by patients, are; fatigue, headache, abdominal distress, or weight change. Patients may also complain more of irritability or difficulty concentrating than of sadness or low mood. Therapy is usually initiated before medication management.
Medication management usually begins with the use of an antidepressant, typically a selective serotonin reuptake inhibitor (SSRI) or serotonin-norepinephrine reuptake inhibitor (SNRI). Improvement with pharmacotherapy can be seen as early as the first 1 to 2 weeks of treatment; however, the efficacy of treatment is generally not evaluated until after 3 to 5 weeks at a therapeutic dose that is believed to increase levels of serotonin in the brain. Serotonin is one of the chemical messengers (neurotransmitters) that transport signals between brain cells. SSRIs block the reabsorption (reuptake) of serotonin in the brain, thus making serotonin more obtainable in the brain. SSRIs are called selective because they appear to affect serotonin, not other neurotransmitters primarily.
Common side effects are Drowsiness, Nausea, Dry mouth, Insomnia, Diarrhea, Nervousness, agitation or restlessness, Dizziness, reduced sexual desire, and headache.
Monitoring should be focused on the risk of suicide within the first few weeks of starting medication, hyponatremia, hyperglycemia, and serotonin syndrome. Serotonin syndrome occurs when there is a high level of serotonin in the body; it can be life-threatening, and signs and symptoms could be life-threatening. Signs and symptoms include High fever, Seizures, Irregular heartbeat, and Unconsciousness.