Schizophrenia is a mental illness with many variations, ranging from keeping to oneself to an extreme - to seeing and hearing things that aren't there. Schizophrenia is usually caused by adolescent trauma and stress. The effects and the symptoms of schizophrenia most often affect people who are 18 to 35 years old.  It is not curable, but is treatable.
There are many different types of Schizophrenia, to name a few, there is:
- Paranoid schizophrenia - Paranoid schizophrenia is the most common type, and is especially prominent in young males. The person is very suspicious of other people. They have hallucinations and delusions, but have delusions more often. 
- Disorganized schizophrenia - The person has trouble with having their words make sense. Also, their emotions aren't always presented at the right times. 
- Catatonic schizophrenia - The person is often quiet, keeps to himself to an extreme extent, In this case, the person is very withdrawn and seems disturbed. 
- Residual schizophrenia - With this type, the person doesn't experience hallucinations and such. The problem is that they have absolutely no motivation. 
- Schizoaffective disorder - The person has the schizophrenia symptoms and mania (extremely changing emotions). 
- Undifferentiated Schizophrenia - What could be called miscellaneous schizophrenia that doesn't fit into any of the latter categories. 
Schizophrenia can be found by running clinical trials only, not by physical tests or tests performed in labs. The latter tests can be used to rule out the other conditions with similar symptoms, thus ensuring that the patient does, in fact, have schizophrenia. Schizophrenia is diagnosed from many symptoms based on patterns, not one single symptom. To diagnose schizophrenia, most use the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, which is standardized criteria for doing such. To be classified as schizophrenic the person must have been having two or more symptoms for one month, at the least. 
Some of these conditions with similar symptoms are: multiple personality disorder, HIV, Syphilis, epilepsy, extreme personality disorders, schizophreniform disorder, and bipolar disorder.  Schizophrenia symptoms displayed in a person are usually positive (traits of psychosis, because Schizophrenia is a kind of psychosis), negative (listlessness, no interest in being social, no fluency while speaking), and cognitive (concentration and thought problems).
Descriptions of some positive symptoms:
- Delusions. Delusions are misinterpretations of what is really happening or having off reasoning. One common example is the delusion of being watched or followed. 
- Hallucinations. Hallucinations are distortions of the way the senses perceive things. For example, hearing voices in ones mind, or seeing things that aren't actually there. 
- Bizarre behavior. Not wanting to reach goals of any kind, and experiencing random agitation.
- Thought problems based on speech. This is a staple of schizophrenia. Speech problems can include: random speech and incoherent speech. 
- Catatonic behavior. Motionlessness and not being aware of the environment. Unusual bodily postures, like contortions. 
Descriptions of some negative symptoms:
- Emotionlessness is where the person cannot express emotions well, as the emotions are suppressed.
- Speech impediments and slow thought processes
- Lack of interest in most things, even things that were once found enjoyable or interesting. 
Diagnostic and Statistical Manual of Mental Disorders
"The Diagnostic and Statistical Manual of Mental Disorders (DSM) is published by the American Psychiatric Association and provides diagnostic criteria for mental disorders." There has been some conflict with relying on it though. It has been revised five times since its creation in 1952, the last revision being in 1994. The cause for the many revisions is that many new disorders keep being discovered. The manual is used to give a diagnoses after the person has been tested.
Causes for Schizophrenia
Schizophrenia develops through inherited genes, social factors, and things the person has grown up with or has experienced previously. Most environmental "stressors" that cause schizophrenia happen during the pregnancy or in the early childhood stages. There is no single, surefire thing that makes people develop schizophrenia. The chance of development completely depends on the person. Stress is a common cause of development of schizophrenia. Other factors that could contribute are: pregnancy complications, physical or mental abuse, an event that could trigger a deep fear, etc.
The only cure for schizophrenia is the treatment of the symptoms themselves, not the schizophrenia disorder. Since the mid-1950s there have been antipsychotic medications which take care of schizophrenia's positive symptoms. Everyone reacts to the medications in different ways. Symptoms for most people are calmed by the sixth week of the treatment.  Some of the more recent antipsychotic drugs are: Risperdal, Zyprexa, Seroquel, Serdolect, and Geodon.  Medication can be taken in pill or syringe form, the syringe form being the longest lasting. Most people are to take drugs for their whole lives, if they don't, they will often relapse. Schizophrenia must always be managed and kept an eye on, similar to the situation of high blood pressure. This can become a problem, especially for those with symptoms which scramble their thought patterns. With many possible mental problems, the person could easily forget to take their drugs.
There is also psychosocial treatment, which has to do with helping the person deal with social and motivational issues by use of methods to handle them.  This treatment can involve talking with a therapist, who helps to give encouragement and information on the disorder.
- Schizophrenia Brian Chiko, 1996-2009.
- Symptoms Brian Chiko, 1996-2009
- Info Wikipedia
- Info on the DSM Wikipedia
- More info on schizophrenia National Institute of Health, April 2, 2008
Other mental illnesses
- Alzheimer's disease
- Asperger syndrome
- Attention deficit hyperactivity disorder
- Bipolar disorder
- Bovine spongiform encephalopathy
- Bulimia nervosa
- Childhood amnesia
- Dissociative identity disorder
- Obsessive compulsive disorder
- Paranoid personality disorder
- Paranoid schizophrenia
- Personality disorder
- Posttraumatic stress disorder
- Walking corpse syndrome