History suggests that schizophrenia has probably been plaguing people and throwing them into social isolation for millennia. Despite the vast amounts of research, the disorder, characterized by bizarre behavior and emotional withdrawal, remains largely a mystery. As many as 24 million people worldwide and about 1 percent of the American population 18 and up have schizophrenia [source: WHO, NIMH]. About 10 percent of those with the disorder end their own lives [source: NIMH]. Schizophrenics often experience delusions, hallucinations, social and emotional withdrawal and unexplainable behavior.

woman with reflection in mirror
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Schizophrenics experience a disconnect with reality.

Although the disorder has probably been present throughout human history, it was not classified accurately until the late 19th century. In the early 20th century, the German psychiatrist Eugen Bleuler came up with the name "schizophrenia," from the Greek words for "split" and "mind," to describe the illness. He chose this term based not on the idea of "split personalities," a common misconception, but rather because schizophrenics experience a disconnect with reality. Bleuler also often referred to the disease in the plural ("schizophrenias") as he recognized that the condition can take an array of different forms.

Schizophrenia or split personality?
Although commonly confused, schizophrenia is not the same as split personality disorder, now known as dissociative identity disorder. Although media and Hollywood have sensationalized Multiple (or "Split") Personality Disorder, it is a serious, though rare condition. The DSM-IV explains that someone with this disorder experiences two or more personalities that take turns controlling the person. It also involves the individual forgetting significant personal information. Often, one personality dominates the individual. Personalities may be drastically different and even criticize each other. Sometimes the different personalities don't know about each other. Treating this disorder involves making the personalities aware of each other and gradually bringing them back into one, possibly through the acknowledgment of a traumatic event that may have triggered the split [source: Encyclopedia Britannica].

Sometimes, it is difficult to distinguish schizophrenia from such conditions as depression or bipolar disorder, which is one reason why it's so important to see a doctor who can rule out other possibilities.

Knowing that the disorder can come so late in life can be frightening for young adults who suspect they might be developing it. So, how do you know if you're experiencing the onset of schizophrenia? Knowing the specific symptoms will help you decide whether you should consult a trained psychiatrist for a diagnosis, and we'll discuss those on the next page.