10.2 Mood disorders

Mood disorders are the most common type of mental illness and they come in two general forms (15%):

1. Depression: aka. major depressive disorder
   • Different from “it’s been a bad day. I’m pretty depressed”
   • severely depressed mood that last two or more weeks. it is accompanied by lack of pleasure, lethargy, and sleep and appetite disturbances.
   • No “reasonable” cause
   • At least 2 weeks, average episode is 12 weeks
   • Affect women more than men. Why? different theories: harder life, less income, poverty, hormone, men are less to report the symptoms, men deny and distract themselves when facing life stressor while women may accept what is going on and ruminate about it.
   • Depression is heritable.
   • Neurotransmitters are involved in depression. Low level of the neurotransmitters norepinephrine and serotonin causes depression. But it is not as simple as this. It usually takes weeks for the drug to work which makes the neurochemical story more complicated.
   • From a psychological level, the core problem seems to be negatively biased thoughts. But there is not much evidence that depressed people had a bad pattern of thought before they had depression. So this pattern of thought is likely to be the consequence of depression, not the cause.
   • The most extreme manifestation of depression is suicide.
2. Bipolar
   • less common than depression, about 1%
   • Swing back and forth from mania to depression