Final answer:
Major Depressive Disorder (MDD) is a common mental disorder characterized by intense feelings of sadness, despair, and other associated symptoms.
Step-by-step explanation:
Symptoms of MDD include mental slowing, loss of concentration, pessimistic worry, agitation, self-depreciation, weight loss, decreased libido, and disrupted sleep patterns.
The exact causes of MDD are not fully understood, but it is believed to be a combination of genetic and environmental factors. Research suggests that there may be a decrease in neurotransmitters such as norepinephrine and serotonin, or an increase in these neurotransmitters, causing the disease. Alternative hypotheses also propose the involvement of dopamine.
Treatments for MDD include psychotherapy, electroconvulsive therapy, deep-brain stimulation, and prescription medications. Different classes of antidepressant medications are available, each working through different mechanisms to alleviate symptoms.
So therefore MDD is a common mental disorder characterized by an intense and persistent feeling of sadness and despair. It is believed to be caused by a combination of genetic and environmental factors, possibly involving changes in neurotransmitter levels. Treatment options include psychotherapy and various medications.