In these debates there is a certain type of parent that has caught my interest. Although they are often educated and articulate, on the subject of vaccinations they can be illogical and unmoved by facts and scientific evidence. Why is this?

As a psychotherapist I have experienced that clear and coherent thinking can be impaired by mental health conditions. Someone with a full-blown Paranoid Personality Disorder has a pervasive sense of distrust and suspicion and is easily recognizable. Not so recognizable are people who do not have the full-blown disorder but do have paranoid personality traits.

People with paranoid personality traits process incoming information on some subjects through a paranoid lens. In other areas of thought they can be quite normal, but on certain subjects, they can be rigid and unfazed by facts. The paranoid lens distorts the most powerful contrary evidence into confirmation of the theory.

Personality structure is complex. Fortunately, life circumstances and troubles have a way of letting people know that maybe their thinking and assumptions need to be re-examined. People can and do change, either with or without professional help.

People with a paranoid tendency are probably a minority, but on this issue they have exerted an influence that may cost lives.