A phobia is an irrational fear resulting in avoidance of the feared object or situation. Examples include fear of animals, storms, or heights. PD patients also can experience symptoms of obsessive-compulsive disorder. Obsessions are recurrent and intrusive thoughts, feelings, ideas, and impulses that cause anxiety and are recognized as being irrational and therefore resisted. Examples of common obsessions include fear of dirt or germs, or excessive worries about finances.
Compulsions are conscious, repetitive behavioral or mental acts which serve to allay anxiety.
It is even possible that anxiety may represent the first sign of the illness for some PD patients. Whether antiparkinsonian medications themselves contribute to anxiety needs to be clarified. There appears to be a strong relationship between movement difficulties and anxiety. It remains unclear whether anxiety is an emotional reaction to difficulties with movement, whether anxiety might worsen these movement difficulties or whether both anxiety and poor mobility occur together as the result of common neurochemical mechanisms in the brain. It remains to be determined whether this represents a particular subtype of depression or whether anxiety occurs as a separate psychatric disturbance.