Halloween has plenty of spooky elements. From ghosts to skeletons to killer clowns, there's something to scare everyone. But what determines what scares people, and how scared they are? Scientists believe genes play a role, and that what scares you may run in the family.
Fear, anxiety, and phobia are all defined differently. Phobias involve intense and unreasonable fear of specific things or situations, while fear is a biochemical and emotional response to the presence of threat, harm, or danger. Anxiety is apprehension, tension, or uneasiness that stems from the anticipation of danger. In other words, phobias are irrational (or irrationally intense), fear is a biological reaction that can have extreme consequences, and anxiety is an anticipation of something that could cause fear.
With these definitions, scientists at the University of Michigan conducted studies to identify genes that may have a correlation with one or all of the above. What they found was complicated. Considering a direct relative with a phobia, an individual is three times more likely to have a phobia as well. Phobias have a lifetime prevalence in the general population of about 10%. This finding is backed up by a twin study, which found that there is a heritability of about 30% for phobias (and anxiety disorders).
Scientists also looked for genes associated with fear in mice. Using specifically bred mice for maximum results, the study narrowed down specific mouse fear traits (such as contextual fear, conditioned fear, and open-field exploration). With two sets of these mice, the scientists found that the defined traits are linked to ‘small, non-overlapping intervals’ on mouse chromosome one. This suggests that there are several genes in the same place that affect fear and anxiety, rather than just one.
Other studies have scanned the human genome to identify fear genes. These studies looked for panic disorder, agoraphobia, generalized anxiety, and specific phobias. Some genes (called loci, denoting a particular place on a chromosome) were specific to very specific disorders; others seemed to be linked to multiple things. Many of these loci have been confirmed in more than one study.
All in all, scientists have determined that there is a definitive genetic aspect of fear. However, this is not to say that genetics are the only cause of fear. Environment, family dynamics, trauma, and many other factors contribute to the formation of phobias, anxieties, and fear responses. By understanding how genes correspond to our response to fear, we can find better ways to deal with it. This is another step in the direction of understanding and treating mental health disorders, as well as understanding human genetics. It seems that scaredy cats do make scaredy kittens!