People with depression have a strong suicidal tendency, and many people think that depression is a mental illness. In the middle of the 20th century, medical research found that the concentration of three neurotransmitters (serotonin, norepinephrine and dopamine) in the brain of depressed suicides is lower than that of normal people. Medical scientists speculate that it is the imbalance in the concentration of these three neurotransmitters that leads to depression.
If the statement 'Depression is not only a psychological disease, but also an organic disease' is true, it will give the above medical scientists the strongest support for their conclusions.