Serotonin and norepinephrine are the primary neurotransmitters involved but dopamine has also been related to depression. A family history of depression is common. Bipolar disorder has a prominent depressive phase but is a different clinical entity from depression. It is reported that more than 30,000 Americans commit suicide each year. The real number is unknown since underreporting is predictably significant.
Suicide is estimated to be the eighth leading cause of death in all age ranges.
Almost all people who kill themselves intentionally have a diagnosable mental disorder with or without substance abuse, which is often a result of attempted self-treatment for the symptoms of depression. No racial preponderance exists in reportable depression or suicide. It is estimated that 8-25 attempted suicides occur for every completion. Many of these are never discovered, or never reported. It is important to understand that the majority of suicide attempts are expressions of extreme distress, not merely bids for attention.