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HALLUCINATIONS AND PSYCHOSIS
http://www.parkinson.org/med32.htm

The term hallucination refers to any perceived sensation which is not real. This could take the form of visual apparitions, imagined voices, non-existent odors, or odd sensations on the skin. In Parkinson's disease, hallucinations are almost always visual in character and are usually due to the effects of dopaminergic antiparkinson medications.

Drug-induced hallucininosis may begin with vivid or disturbing dreams. Often hallucinations occur in low light situations, and when the individual is going from one state of consciousness to another, such as waking from sleep.

Someone might "see" a relative in the bedroom upon awakening, but then realize the person is not really present. Something may be seen darting out of the corner of the eye, or crawling bugs will be seen in patterned wall coverings or floor tiles.

Seeing small people, children and animals are common hallucinations. As hallucinations become more vivid, insight into the unreality of the perception is lost, and the patient may be unable to distinguish real from hallucinatory experiences.

Confusion and suspicious paranoid delusions can also occur. The state of confusion and hallucinations is termed psychosis. Unfortunately, a delusional individual often directs his suspicions towards a spouse or other family member. For example, he may suspect the spouse of infidelity or a son or daughter of financial misdeeds.

Uncontrolled hallucinations and psychosis can pose a safety concern. The psychotic person may try to flee the residence, or arm themselves in order to escape or fend off a perceived attacker. Even when safety is not compromised, the agitated behavior and accusations disrupt the entire household or nursing care facility.

Hallucinations and confusional episodes most often occur at night; this nocturnal confusion is referred to as sundowning. The altered sleep-wake pattern in Parkinson's disease may also play a role in these events. Perhaps darkness, artificial lighting, and shadows after sunset make individuals more susceptible to visual misperceptions.

Vivid dreams alone usually do not warrant medical therapy. Sleep remedies discussed in the following chapter may be used if necessary. Similarly, occasional visual hallucinations with insight retained may not require any action beyond reassurance.

There are three basic steps in the assessment and treatment of disturbing hallucinations and delusions:

1 determine the probable cause
2 reduce or withdraw the offending medication(s)
3 add an antipsychotic medication

Medications such as levodopa are often the cause of increasing confusion or hallucinations.

Other medications given for reasons beyond the PD, such as narcotic analgesics (pain relievers), can be the cause as well. The list of prescription drugs which can cause psychotic side effects is very long. Some drugs alter the absorption and breakdown of antiparkinson medications, and thus may cause or lessen these side effects.

Hallucinations and confusion can even be triggered by over-the-counter medicines, as occasionally occurs with the cough medicine dextromethorphan.

Some patients suddenly develop these symptoms because of other illness such as an unrecognized urinary tract infection or congestive heart failure. Finally, some individuals develop hallucinations or psychosis in the absence of medications and co-existing illness. This suggests that the patient may have a less typical form of Parkinsonism such as diffuse Lewy body disease.

When hallucinations or delusions become problematic, the patient or care partner should notify the neurologist or primary care physician. If it is determined that the probable source is the antiparkinson medication, the obvious solution is the reduction or discontinuation of one or more of the drugs.

CHOOSING AN ANTIPSYCHOTIC MEDICATION

Some  of the milder medications in this category (Haldol)can be used at low doses for short periods of time,  but should not be used for prolonged therapy.

An exception is the drug clozapine (Clozaril®). It has been demonstrated to alleviate the psychotic symptoms without worsening the motor problems. Very small doses, ¼ to ½ of a 25 mg. tablet, given at bedtime is a common starting dose.

Higher doses of this medication can cause excessive sedation, drooling and low blood pressure. Unfortunately, the use of clozapine requires frequent blood tests; the medication has been rarely associated with
agranulocytosis, a depletion in the white blood cells which fight infection.

Newer medications such as olanzapine (Zyprexa®) are now being tested to treat psychosis in patients with Parkinson's disease, but the results of clinical trials are not yet published.

The following table summarizes antipsychotic drugs and their relevance to the Parkinson population

ESTABLISHED DRUGS IN THE TREATMENT OF HALLUCINATIONS AND PSYCHOSIS IN PD
-clozapine (Clozaril®)
NEWER DRUGS WITH UNCERTAIN TOLERABILITY AND EFFECTS IN PD
olanzapine (Zyprexa®)
quetiapine (Seroquel®)
risperidone (Risperdal®)
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Both these drugs have been mentioned as being prescribed for HD.   Of interest:

-clozapine therapy has been associated with a potentially serious adverse effect, idiosyncratic agranulocytosis. As a result, frequent blood counts are required for patients taking  this medication.
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Olanzapine and Clozapine: Comparative Effects on Motor Function in Hallucinating PD Patients
Goetz CG, Blasucci LM, Leurgans S, et al
Neurology. 2000;55:789-794

Hallucinations and other behavioral disturbances are seen in approximately one third of patients with Parkinson's disease (PD) treated chronically with dopaminergic agents. The pathogenesis of these hallucinations is unknown although disturbances in the dopaminergic and serotonergic pathways probably contribute to the process. In the past, reducing the dose of the antiparkinsonian medication was the only treatment available that reduced the chance of developing hallucinations.

The introduction of clozapine has allowed patients to continue taking their dopaminergic medication  while treating the drug-induced hallucinations. Presently, clozapine is considered the drug of choice in the treatment of PD-associated psychosis. Clozapine is a tricyclic dibenzodiazepine derivative that has high potency in treating psychosis with minimal central dopaminergic antagonism.

Clozapine appears to be more active at the limbic dopamine receptors than at the striatal receptors and does not induce parkinsonism or tardive dyskinesias. In addition, clozapine has been shown to treat some of the movement disorders associated with PD (eg, tremor, dystonia, and dyskinesia) by a direct mechanism that is independent of the antipsychotic effect.

Unfortunately, clozapine therapy has been associated with a potentially serious adverse effect, idiosyncratic agranulocytosis. As a result, frequent blood counts are required for patients taking this medication.

The primary dysfunction responsible for the olanzapine-associated decline was bradykinesia and gait. In addition, clozapine-treated patients showed significant improvement in reduction of hallucinations and overall behavior while olanzapine had no effect.

Although the study was stopped before full enrollment was achieved, the results suggest that olanzapine may exacerbate parkinsonism in patients with PD who have hallucinations in comparison to clozapine. Clozapine therapy appeared to be associated with a modest improvement in parkinsonism  and significant improvement in the overall behavioral assessment.

Source: Medscape