1. Mood Disorders
characterized by emotional extremes

2. Depression
Referred to as the common cold of psychological disorders.

3. Major Depressive Disorder
A person, for no apparent reason, experiences two or more weeks of depressive moods and feelings of worthlessness, lethargic, little interest in family, friends, or activities that they usual do

4. Persistent Depressive Disorder
Aka: Dysthymia
Suffering from mild depression every day for at least two years.
Poor appetite or overeating
Insomnia or hypersomnia
Low energy or fatigue
Low self-esteem
Poor concentration
Difficulty making decisions
Feelings of hopelessness

5. Bipolar Disorder
Person alternates between the hopelessness and lethargy of depression and the overexcited state of mania.