About 40 percent of Parkinson's disease patients struggle with anxiety, often in tandem with depression. So-called generalized anxiety makes individuals so worried and edgy that they can't sleep or they experience a racing heartbeat, shortness of breath, and sweating. Such symptoms can be provoked by distress and embarrassment over how others may react to seeing their Parkinson's tremor or shuffling gait, and the problem can hurt their ability to perform at work or enjoy social gatherings. Even worse, anxiety itself can aggravate Parkinson's motor symptoms.

People with Parkinson's also often suffer anxiety when their levodopa or dopamine agonist drugs start wearing off. They fear that the next dose won't control their symptoms again, or that they'll be stranded out in public, unable to move well. Extreme anxiety can produce scary panic attacks that leave the patient unable to breathe and feeling as if he's having a heart attack. For some, social situations provoke such an intense bout of nerves that they develop a social phobia and shun any gatherings.

Anxiety disorders can be allayed with SSRI antidepressants or antianxiety drugs such as Valium.