10 Medically Unexplained Mental Illnesses Will Make You Think Your Family Members Are Impostors

3. Rett Syndrome

Rett syndrome affects babies and occurs almost exclusively in girls. Babies who are born with this syndrome appear to develop normally for about six months. Then they progressively lose their ability to control the muscles that help them move, coordinate, and communicate.

Babies with Rett syndrome often have smaller heads due to slowed brain growth. As they get older, this delayed growth becomes more noticeable in the other parts of their bodies.[8]

For now, there is no cure. Current treatments attempt to improve the child’s movements and communication as well as support the family.

2. Bobble-Head Doll Syndrome


Bobble-head doll syndrome also affects children, often around age three. It causes them to bob their heads up and down or side to side. If they try, the children can prevent the bobbing. It also disappears when they sleep. But if the child becomes excited or isn’t concentrating, then the bobbing worsens.

As children spend a lot of time being excited or not concentrating, this can be quite a problem. Luckily, it does not appear to be fatal. In fact, the disorder can be cured quite readily as it is caused by a cyst in the brain. Once the cyst is removed, the syndrome either disappears or its symptoms are significantly reduced.[9]

1. Synesthesia

For people with synesthesia, one sense, such as hearing a noise or smelling an odor, simultaneously activates another sense. Of course, not all individuals react to every stimulus. There are different kinds of synesthesia.

In the case of sight, you may see a specific color whenever you perceive a certain letter or number. With taste, a certain noise may trigger a specific taste in your mouth. Usually, only two senses are linked. However, in rare cases, synesthesia can link three or more. In fact, the word “synesthesia” comes from Greek and translates to “joined perception.”

Women are three times as likely as men to have the condition. Synesthetes are also more likely to be left-handed and have someone else in their families with the condition. Estimates of the number of people with synesthesia vary wildly—from 1 in 200 to as few as 1 in 100,000.

Although scientists don’t know which areas of the brain are involved with synesthesia, some believe that this condition is caused by “crossed wires” within the brain. Other research points to the limbic system (which regulates emotional responses) as being responsible for this syndrome.[10]

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