While depression is the most common psychiatric problem in HD, a smaller number of patients will become manic, displaying elevated or irritable mood, overactivity, decreased need for sleep, impulsiveness, and grandiosity. Some may alternate between spells of depression and spells of mania with times of normal mood in between, a condition known as bipolar disorder.
Patients with these conditions are usually treated with a mood stabilizer. Lithium is probably still the most popular mood stabilizer for people with idiopathic bipolar disorder, but we have not found it to be as helpful in patients with HD. It is not known why this is the case. Lithium has a narrow therapeutic range, particularly in patients whose food and fluid intake may be spotty, but there may be some other aspect to the mood disorders found in HD patients which make them poor lithium responders.
We recommend beginning with the anticonvulsant divalproex sodium (Depakote) or valproic acid (Depekene) at a low dose such as 125 to 250mg po bid and gradually increasing to efficacy, or to reach a blood level of 50-150mcg/ml. A dose of 500mg po bid is fairly typical, but some patients will require as much as several grams per day.
Another anticonvulsant, carbamazepine (Tegretol), is also an effective mood stabilizer. This can be started at 100-ZOOmg per day, and gradually increased by lOOmg/day to reach an effect or a therapeutic level of 5-IZmcg/ml, which may require a dose of 800-1 ZOOmg/day.
Therapeutic ranges for these drugs were established on the basis of their anti-convulsant properties, so it is important to remember that a patient may show a good psychiatric response below the minimum "therapeutic" level (but generally should not exceed the maximum level in any case).
Both drugs carry a small risk of liver function abnormalities (particularly divalproex sodium) and blood dyscrasias (particularly carbamazepine), and so LFT's, and CBC should be routinely monitored every few months and clinicians should be alert for suggestive symptoms.
Valproic acid may cause thrombocytopenia, and both drugs are associated with neural tube defects when used during pregnancy.
Manic patients with HD who have delusions and hallucinations may require a neuroleptic, and patients who are very agitated may need a neuroleptic or a benzodiazepine for immediate control of these symptoms.
As discussed for depression, the doctor may wish to prescribe one of the newer anti-psychotics which have fewer parkinsonian side effects, such as risperidone, olanzepine, or quetiapine.
In cases of extreme agitation, a rapidly acting injectable agent, such as droperidol (Inapsine) or lorazepam may be necessary. Finally, ECT is known to be a very effective treatment for idiopathic mania and should be considered when other treatments fail, or when the individual is extremely dangerous.