This disorder is called PTSD, or Post Traumatic Stress Disorder.
PTSD is a condition that may last a few months or even years, with triggers that may bring forth memories of the trauma accompliced with powerful physical and emotional tics. Symptoms of PTSD can include nightmares or stressful, unwanted and uncontrollable memories of the scene. Certain treatment options can include different types of trauma-focused psychotherapy and special medications to manage PTSD symptoms. PTSD is usually associated with war veterans and murder witnesses.
An heterozygote advantage is when a heterozygous genotype has a greater aptitude than homozygous genotypes. The specific case of heterozygous advantage over a single locus is known as overdominance. In short, this happens when a disorder is present in a heterozygous population, but this disorder has a great benefit for the genes present in the body.
