Summary: Genetic Role In Phobia

Introduction: Genetic Role in Phobia(s): When grouped with generalized phobia and other anxiety disorders, some estimates place the rate of individuals suffering from anxiety at some point in their life as high as 25% (Kessler, 1994). Due to the high rates of anxiety disorders, the genetic link merits consideration and must be thoroughly evaluated. The majority of evidence indicates there is a consistent, albeit modest contribution of genetic factors to the development of specific phobias. This ‘modest contribution’ means that the predisposition for specific phobias can be passed down from parents to children. One unique, apparent exception to this rule that appears time and time again in published studies is a SP known as blood-injection

The evidence gathered from these studies shows the strongest genetic correlation for agoraphobia, the weakest for SP, and falls somewhere in between for social phobia. One problem of the twin studies looking for the genetic contribution to specific phobia in particular is that the twins experience a similar, if not identical familial and social environment during their development and upbringing. This calls into question the external validity of these studies. Another limitation is the fact that, specific phobias, social phobia, generalized social phobia, and agoraphobia are sometimes lumped together due to the scarcity of subjects to study in each of the individual categories. The genetic causes, if present, may be common or they may not

A condition known as joint hypermobility syndrome, or joint laxity, has been strongly connected to anxiety disorders. At first glance, this information seems hardly intriguing, but after researchers examined the correlation in more detail an alteration to chromosome 15 was discovered involving a duplication at 15q24-26. The researchers then gathered 70 phobic and unrelated patients attempting to look for this duplication. The duplication was found it in 68 of the subjects.
These two pieces of data are among the most important gathered to date; yet they are not without a significant drawback. When conducting the research, the researchers did not seem to distinguish between panic disorder and phobic patients. They were grouped together in a single category and a detailed clinical description of the patients was not included. The data is still highly relevant but the possibility that PD and phobia have different genetic causes cannot be discounted.
Summary: Youth studies and animal research has provided additional insight in regards to the neurocircuitry of threat assessment, learning about potentially threatening stimuli or situations, and mounting physiologic responses to conditions that provoke these stimuli (Aggelton, 1992, LeDoux