Depression is predicted to be the second largest contributor to the global burden of disease by the year 2020. By 2030, depression will be the #1 contributor to the global burden of chronic disease in high-income countries.
There is a greater than 16% lifetime risk of major depressive disorder (MDD). Persons living below the poverty level are nearly 2½ times more likely to have depression. 43% of persons with severe depressive symptoms report serious difficulties in work, home, and social activities.
For starters, I take issue with the word “disorder” in attention deficit disorder (ADD). It’s not a stretch to suggest that ADD is actually a normal physiological response to the many insults of the modern world. The hyper-vigilance, distractibility, and impulsivity of ADD could all be predictable evolutionary adaptations intended to help us be safer and more successful in stressful environments.
Stress is not just mental, it quickly jumps to a physiologic effect. When the brain perceives stress, it sends both chemical and nerve signals to the adrenal glands ordering them to make two short-term stress hormones [epinephrine and norepinephrine] and the long-term stress master hormone cortisol. Not eating regularly enough and getting low blood sugar also spike cortisol levels. Cortisol is now known for promoting the dreaded stress-gut that gives chronically stressed people that apple shape.
Epinephrine and norepinephrine both promote the “fight or flight” response to the world by stimulating increased tone in the sympathetic nervous system. Other attributes of the “sympathetic state” are the tendency to freeze up, tense muscles, shallow breathing, and divert blood flow away from the extremities and digestive tract toward the large muscles. The sympathetic nervous system also interrupts digestion and makes it harder to concentrate and integrate and make new memories. If you have ever had trouble getting someone else (or yourself) to see a new point of view in a heated argument, you can probably thank the sympathetic nervous system for that gem of human psychology.
It all makes perfect sense if you think about it; if your body senses a threat (stress) it gets everything ready for a fight or flight from danger. Cortisol helps us prepare for stress by mobilizing resources to raise blood glucose and cholesterol. This sugar boost is good if you’re about to sprint away from an angry rhinocerous, but not so good (AKA promoting diabetes and heard disease) if the stress is an email or a phone call.