Schizophrenia treatment focuses on traditional antipsychotic drugs, which block dopamine receptors in the brain. Traditional antipsychotic drugs provide varying degrees of effective schizophrenia treatment depending on an individual's symptoms. Newer "atypical" antipsychotics such as zyprexa, seroquel, and risperdal provide schizophrenia treatment for symptoms resistant to traditional antipsychotic medication. Whether traditional or atypical, all antipsychotic drugs can cause side effects, including tardive dyskinesia and Parkinson's-like side effects.

Traditional Antipsychotic Drugs and Dopamine

Traditional antipsychotic drugs are the mainstay of schizophrenia treatment. You may hear antipsychotic drugs referred to by other names: antischizophrenics, neuroleptics, and major tranquillizers.

It is thought that antipsychotic drugs provide schizophrenia treatment by affecting the brain's dopamine levels. Dopamine is a neurotransmitter: a brain chemical responsible for the transmission of nerve cell signals. Dopamine imbalances are a possible cause of schizophrenia.

Antipsychotic drugs block dopamine receptors, limiting nerve cells from utilizing dopamine. While many researchers believe antipsychotic drugs' ability to block dopamine is key to their successful schizophrenia treatment, some schizophrenia experts disagree. Critics for the dopamine theory don't doubt antipsychotic drugs provide relief from schizophrenia symptoms. They do, however, point out antipsychotics block dopamine receptors quickly, but the benefits of schizophrenia treatment are not seen until days to weeks later. If the antipsychotic drugs do not treat schizophrenia by blocking dopamine, the medication may act on some other brain process, which provides schizophrenia relief.

Positive Symptoms and Traditional Antipsychotic Drugs

Antipsychotic drugs provide the most effective schizophrenia treatment to patients with predominantly positive symptoms. Positive symptoms describe schizophrenia symptoms that arise through excessive functioning: hallucinations, disorganized speech, and delusional thinking are all positive schizophrenia symptoms. "Negative" symptoms of schizophrenia (dulled emotions, loss of motivation, impaired visual ability) do not respond as well to traditional antipsychotic drugs.

Common Traditional Antipsychotic Drugs

If a schizophrenic patient receives treatment with traditional antipsychotic drugs, he or she will most likely receive one of the following medications:

• chlorpromazine (Thorazine^®)
• flupenthixol (Fluanxol^®)
• haldol (Haloperidol^®)
• loxapine (Loxapac^®, Loxitane^®)
• perphenazine (Etrafon/Trilafon)
• prolixin (Fluphenazine Decanoate, Modecate^®, Permitil^®)
• trifluoperazine (Stelazine^®).

Atypical Antipsychotic Drugs: Zyprexa^®, Seroquel^® and More

Schizophrenia treatment options have increased with the development of "atypical" antipsychotic drugs such as Zyprexa^®, Seroquel^® and Risperdol^®. While the main function of traditional antipsychotics was to block dopamine receptors, many atypical antipsychotic medications block both dopamine and serotonin (like dopamine, serotonin is a neurotransmitter).

Serotonin imbalances have been linked to depressive mood disorders, whose symptoms have much in common with negative schizophrenia symptoms. This may explain why atypical antipsychotics appear to provide better schizophrenic treatment to patients with predominantly negative symptoms.

Common Atypical Antipsychotic Drugs

• aripiprazole (Abilify^®)
• clozapine (Clozaril^®)
• olanzapine (Zyprexa^®)
• quetiapine (Seroquel^®)
• risperidone (Risperdal^®)
• ziprasidone (Geodon^®, Zeldox^®).

Schizophrenia Treatment Side Effects

Whether traditional antipsychotic drugs or atypical antipsychotics, all schizophrenia treatment produce side effects. In fact, so common are side effects associated with schizophrenia treatment that all patients experience some degree of side effects.

Common side effects associated with schizophrenia treatment include:

• anxiety
• blurry vision
• cannot sit still/restless
• changes in breast shape or size
• constipation
• difficulty concentrating
• difficulty urinating, excessive urination
• dizziness
• drooling
• dry mouth
• excessive saliva
• fatigue
• headache
• increased hunger
• increased thirst
• insomnia
• memory problems
• menstrual period changes
• muscle trembling
• nausea and vomiting
• sexual dysfunction
• sleepiness
• slow movement
• stiff muscles
• weight loss or weight gain.

Parkinson's Like Side Effects and Schizophrenia Treatment

When antipsychotic drugs block dopamine receptors, the brain may not be able to access sufficient dopamine. Low levels of dopamine are associated with Parkinson's disease, and artificially low dopamine levels caused by antipsychotic drugs may produce Parkinson's-like side effects. Such side effects include stiffness, shakiness, and slow movement.

Parkinson's-like side effects associated with schizophrenia treatment can be minimized in some cases by administering anticholinergic drugs (that block the neurotransmitter acetylcholine) in combination with antipsychotics.

Tardive Dyskinesia Side Effects

Long-term schizophrenia treatment may result in tardive dyskinesia side effects. Tardive dyskinesia causes compulsive chewing movements, lip puckering, lip smacking, and tongue rolling. Tardive dyskinesia side effects usually stop when antipsychotic drug treatment is discontinued, but in some cases becomes permanent. New schizophrenia treatment, most notably the atypical antipsychotic risperdal, may have lower chances of tardive dyskinesia than standard treatment.

Schizophrenia Treatment Clinical Trials

Schizophrenia treatment is constantly evolving as research and clinical trials produce new medication and treatment options. At present, schizophrenia clinical trials are recruiting for clinical trials centered around new antipsychotic drugs and treatments such as:

• DTA 201A (dopamine receptor blocker)
• DU 127090 (dopamine receptor blocker)
• iloperidone (dopamine receptor blocker)
• MEM 3454 (nicotinic alpha-7 receptor activator)
• ORG 5222 (dopamine receptor blocker)
• osanetant (neurokinin-3 blocker).

Resources

Beers, M.H., & Berkow, R. (ed). Schizophrenia and related disorders. The Merck Manual of Diagnosis and Therapy, 17th Edition. Merck Research Laboratories, NJ, 1999.

Fauci, A., Braunwald, E., Isselbacher, K., Wilson, J., Martin, J., Kasper, D., Hauser, S. & Longo, D. (ed). Harrison's Principles of Internal Medicine, 14th Edition . McGraw-Hill, New York, 1998.

Murphy, M., Cowan, R. & Sederer, L. Blueprints in Psychiatry. Blackwell Publishing, Massachusetts, 2004.