There are may environmental risk factors factors for schizophrenia such as drug use, stress before birth and in some cases exposure to infectious diseases (a disease that spreads from person to person). In addition, living in a city during childhood or as an adult has been found to double the risk of schizophrenia . This is true even after taking into account drug use, race, and the size of one’s social group. Other factors that play an important role include whether the person feels socially isolated, as well as social adversity, racial discrimination (treating a person badly because of their race), the person's family not working properly, unemployment, and poor housing conditions. There is evidence that childhood experiences of abuse or trauma are risk factors for developing schizophrenia later in life.
Several drugs have been linked with the development of schizophrenia and the abuse (harmful use) of certain drugs can cause symptoms like those of schizophrenia. About half of those people who have schizophrenia use too much drugs or alcohol, possibly to deal with depression, anxiety, boredom, or loneliness. Frequent marijuana use may double the risk of serious mental illness, including schizophrenia.
More people with schizophrenia smoke than the general population; it is estimated that at least 60% to as many as 90% of people with schizophrenia smoke. Recent research suggests that cigarette smoking may be a risk factor for developing schizophrenia. Smoking also reduces the effects and side effects of anti-psychotic drugs, and this may be one of the reasons for the high smoking rate. Patients taking anti-psychotic drugs die up to 20 years earlier than others, possibly because the medication makes them overweight, gives diabetes and leads to them smoking.
Factors such as lack of oxygen, infection, or stress and lack of healthy foods in the mother during pregnancy, might result in a slight increase in the risk of schizophrenia later in life. People who have schizophrenia are more likely to have been born in winter or spring (at least in the northern half of the world). This might relate to increased rates of exposures to viruses before birth. This difference is about 5 to 8 percent.
Some people who have schizophrenia have differences in their brain structure compared to those who do not have the disorder. These differences are often in the parts of the brain that manage memory, organization, emotions, the control of impulsive behavior, and language. For example, there is less brain volume in the frontal cortex and temporal lobes, and problems within the corpus callosum, the band of nerve fibers which connects the left side and the right side of the brain. People with schizophrenia also tend to have larger lateral and third ventricles. The ventricles are spaces within the brain filled with cerebrospinal fluid.
The human brain has 100 billion neurons; each one of these neurons are connected to many other neurons. One neuron may have as many as 20,000 connections; there is between 100 trillion and 500 trillion neural connections in the adult human brain. There are many different parts or 'regions' of the brain. To complete a task - like recalling a memory - usually more than one region of the brain is involved, and they are connected by neural networks which is like the brain's wiring. It is believed that there are problems with the brain's wiring in schizophrenia.
The DSM-IV-TR or the ICD-10 criteria are used to determine whether a person has schizophrenia. These criteria use the self-reported experiences of the person and reported abnormalities (unusual occurrences) in the behavior of the person, followed by a clinical assessment. A person can be determined to have the disease only if the symptoms are severe.
There are various medical conditions, other psychiatric conditions and drug abuse related reactions that may mimic the symptoms of schizophrenia (meaning they have some or all of the same symptoms). For example, delirium can cause visual hallucinations, or an unpredictable changing levels of consciousness. Schizophrenia occurs along with obsessive-compulsive disorder (OCD), a disorder in which a person becomes obsessed with certain ideas or actions. However, separating the obsessions of OCD from the delusions of schizophrenia can be difficult.
There is no clear evidence that treating schizophrenia with anti-psychotic drugs early is effective. The British NICE guidelines recommend cognitive behavioural talk therapy for all people at risk. In recent research, 76 patients at risk for schizophrenia were divided into two groups. One group got omega3 for 3 months and the other got a dummy pill (food oil). After 12 months only 4.9% of the omega 3 group had got schizophrenia compared to 27.5% in the other group. There is some evidence which shows that early treatment with drugs improves short term outcomes for people who have a serious episode of mental illness. These measures show little benefit five years later. Attempting to prevent schizophrenia in the pre-onset phase with anti-psychotic drugs is of uncertain benefit and so is not recommended (as of 2009). Prevention is difficult because there is no reliable way to find out in advance who will get schizophrenia.
The treatment of schizophrenia is based upon the phase of the illness the person is in. There are three treatment phases:
There are some goals during the acute phase of treatment. Some of these goals are to prevent harm. To prevent harm, the person being treated will have the severity of psychosis and it's symptoms reduced. These symptoms include agitation, aggression, negative symptoms, self-disorder, and thought disorders. Another goal is to find and treat the things that led to the episode of psychosis. Then, the person will be treated by trying to go back to how they were before psychosis. Lastly, the person will be helped by forming social connections and finding out what treatment plans work for them. Some treatment plans can be for a long time, and others can be for a short time.
The stabilization phase also has goals. One is to reduce the stress the person feels. Another is to prevent the person from experiencing psychosis again. Then, the person is helped further with social connection and getting better. If the person has improved with a medication, it is recommended they keep taking it for at least 6 months.
The last phase of treatment is to make sure that the person is improving. If the treatment has bad side effects, it may be changed in this phase. Some treatments during this stage are psychotherapy and medication. Antipsychotic medications greatly reduce the risk of the person experiencing psychosis again. They are strongly recommended.
The first-line psychiatric treatment for schizophrenia is antipsychotic medication, which can reduce the positive symptoms in about seven to fourteen days. However, medication fails to improve negative symptoms or problems in thinking significantly. Many antipsychotics are Dopamine antagonists (a substance interfering with how another substance works.) High concentrations of Dopamine are thought to be the cause of hallucinations and delusions. For this reason blocking Dopamine reception helps against hallucinations and delusions.
The British national guidelines for treatment (NICE) suggest checking for reactions to traumatic experiences, deciding together with a doctor about using medication, taking into account the side effect risks of getting diabetes, becoming seriously overweight, getting brain damage (tardive dyskinesia, 5% risk per year), men growing breasts, and feelings described as inner torture (akathesia). The guidelines warn against using more than one antipsychotic drug at the same time.