This aggregation is stronger in BII phobia than in any other known phobic disorder: upwards of 60% of those with the phobia have first-degree relatives who are also BII-phobics. It is believed that this evidences the phobias genetic underpinnings. One study estimated actual heritability of the phobia at 59%.Additionally, a majority of phobics attribute their fear to environmental factors. For instance, some sort of traumatic event involving blood, injury, or injection that conditioned them to fear those particular stimuli. Others self-report being conditioned by seeing another person react to the stimuli with a consistent pattern of fear.It has been theorized that exhibiting vasovagal response when exposed to blood was evolutionarily advantageous, and that this phobia is a vestige of an ancestral evolutionary mechanism. Fainting may have acted as a form of tonic immobility, allowing primitive humans to play dead in a situation where blood was being spilled, perhaps helping them to avoid the attention of enemies. It has also been suggested that the drop in blood pressure associated with seeing blood — as with an individual seeing blood from their own wound — occurs in order to minimize blood loss. Treatments
Individuals typically seek therapeutic treatment for BII phobia in a bid to alleviate symptoms that arise when exposed to a phobic trigger.
BII-phobics may be given pictures of needles or blood, asked to illustrate needles or scenes with blood, or to speak about their phobic triggers. This systematically progresses to the point of the individual directly confronting a phobic stimulus: being given a needle, witnessing blood being drawn, etc. As exposure continues, it is expected that the phobic response will become less pronounced, and symptoms less debilitating.While AT targets the phobia’s physiological response, aiming to raise blood pressure and directly prevent fainting, AR focuses mainly on helping an individual avoid the phobia’s associated anxiety. A phobic will learn progressive relaxation techniques to help to calm themselves upon exposure to a trigger. Temporary alleviation of symptoms
Drinking water before a triggering experience such as blood donation has been indicated to aid in prevention of a fainting response. Water will increase sympathetic nervous system activation, raising blood pressure and combating vasovagal response.Certain physical maneuvers also have the capacity to temporarily boost blood pressure, alleviating symptoms of pre-syncope like lightheadedness by boosting blood flow to the brain. These include the phobic individual crossing their legs, making tight fists with both hands, or engaging muscles of the trunk or arms. Coughing, which can similarly increase cranial blood flow, can also be useful as a coping mechanism to avoid pre-syncope and syncope.Symptoms of a phobic response are generally able to be fully alleviated within a few minutes simply by removing the phobic trigger.