General paresis is an impairment of mental function caused by damage to the brain from untreated syphilis.

General paresis is one form of neurosyphilis. Today it is very rare.

The syphilis infection damages the nerves of the brain. This damage causes:

• Abnormal mental function including hallucinations and false ideas (delusions)
• Brief, sharp, "lightning" pains that occur with tabes dorsalis
• Decreased mental function
• Eye changes and abnormal pupil response
• Mood changes
• Overactive reflexes
• Personality changes
• Speech changes

General paresis usually begins about 15 - 20 years after the syphilis infection. Risks include syphilis infection and infection with other sexually transmitted diseases, such as gonorrhea (which may hide symptoms of syphilis infection).

Syphilis infections are passed through sexual contact with an infected person, but may also be transmitted by nonsexual contact.