Obesity: The state of being overweight by 20 - 30 percent of the ideal body weight. See related article on Teen Obesity

Obsessive-Compulsive Disorder: Obsessions: There are persistent thoughts, impulses or images that are recurring.  Compulsions: This includes the repetitive behaviors, such as locking doors and windows, cleaning, washing hands, counting, etc.  Both of which cause the individual stress and can turn into all encompassing activities leaving little time for anything else. See related article on Personality Disorders

Opiates: Opiates are considered any medication or drug derived from the Opium Poppy.  These would include Morphine, Codeine, and Heroin.  These substances are used in pain management and are highly addictive.  Heroin is the most addictive and dangerous, as it is sold on the street in different forms.  Many, many deaths have occurred due to Heroin usage, overdosage, etc.  Heroin users have seen an increase in infections such as Hepatitis and HIV.

Oppositional Defiant Disorder: Hostile, negative and defiant behaviors.  This is accompanied by a willful and wanton disregard for social standards and values.  These behaviors can only be considered ODD if the behaviors are more frequent than another individual of comparable age and developmental level.

Oral Sex: A sexual act where a person's mouth is used to stimulate another's genitals. See related article on Oral Sex

Oxycontin: Oxycontin and Oxycodone are very powerful pain relievers.  This pain reliever offers a heroin like high.  it is similar to codeine, however much more powerful and addictive.