The Causes of Obsessive-Compulsive Disorder and Other Anxiety Disorders

Causes of Obsessive-Compulsive Disorder

Having cost the United States an estimated 6% of the total 1990 US mental health care bill of $148 billion, the causes of obsessive-compulsive disorder are actively researched -- but it is by no means the only anxiety disorder receiving such research attention.

Much work focuses on the role of a deep brain structure called the amygdala and the role it plays in the dynamics of fear and anxiety. Acting as a sort of crossover point for areas of the brain which initially process afferent, or incoming, signals and those areas which begin to imbue them with meaning, it is thought that activity in the amygdala may trigger fear and anxiety. Playing an important role in memory formation, the hippocampus stands out as another area of brain tissue which may be implicated in anxiety disorders, particularly PTSD (posttraumatic stress disorder). Recent studies have suggested that this area of brain tissue may actually shrink in individuals who have experienced severe stress or trauma (as well as in individuals suffering mood disorders such as chronic major depression). Finally, some research suggests the basal ganglia and striatum may be implicated in the experience of obsessive-compulsive disorder.

Other studies focus on differences in anxiety responses between twins and between members of families; at this stage, it appears that both heredity and environmental factors have a role to play in the development of anxiety disorders. It is possible, for instance, that while trauma itself acts as a trigger for posttraumatic stress disorder, genetic factors may predispose some individuals toward being more or less susceptible to developing the full-blown disorder.

The upshot? No clear answer has yet emerged to the question of what causes obsessive-compulsive disorder or the other anxiety disorders, but parts of an overall picture are beginning to fall into place which will hopefully make for steadily improving treatment for the millions of people who suffer from the disorders every year.