These conditions affect emotions. Depression causes a feeling of deep sadness. Bipolar disorder goes back and forth from being very sad to being very happy.
Disease
Movement disorders
Learn about the different types of neurological conditions that affect movement.
Disease
Moyamoya disease
This rare condition happens when blood flow to the brain is blocked or narrowed and a tiny cluster of blood vessels forms at the base of the brain.
Disease
Muscular dystrophy
Find out about the various types of this condition, which affects muscles over time. Then learn about treatments to help with the symptoms.
Learn about the symptoms, diagnosis and treatments for this autoimmune disease that attacks nerve fibers in the body.
Disease
Narcissistic personality disorder
This mental disorder includes an unreasonably high sense of importance, a need for excessive admiration, fragile self-esteem, and troubled relationships.
Disease
Nicotine dependence
Learn about the chemical in tobacco that makes it hard to stop smoking. Then find out about treatments and resources to help you quit.
Disease
Niemann-Pick disease
A condition passed down in families that affects how the body breaks down and uses fats. Fat buildup in cells damages the nerves, brain and other organs.
Disease
Nightmare disorder
Nightmare disorder involves disturbing or scary dreams that awaken you, causing distress or preventing adequate sleep.
Disease
Nonalcoholic fatty liver disease
This liver condition is becoming more common in the Western world. Find out how to treat and prevent this potentially dangerous liver disease.
Disease
Obsessive-compulsive disorder (OCD)
OCD features unwanted thoughts and fears, or obsessions. These obsessions lead to repetitive behaviors, also known as compulsions, that get in the way of daily activities.
Disease
Oppositional defiant disorder (ODD)
This childhood mental health condition includes frequent and persistent anger, irritability, arguing, defiance or vindictiveness toward authority.