# 18 - Neurological effects

# Neurological effects

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and in non-responsive rapid cyclers with bipolar disorder, using thyroxine to treat subclinical 
hypothyroidism may be beneficial for the mood disorder. 
Polycystic ovaries (PCO): 25 - 33% UK population of adult females have PCO morphology 
notable in ultrasound. 5-26% may have actual PCOD, which is defined as having PCO in 
ultrasound with hyperandrogenism or LH disturbance. 10% woman on valproate have new onset 
PCOD. The relative risk is 7.5 for PCOD. On stopping most people remit from PCOD. 
The exact mechanism by which valproate might causes PCOD remains unknown, although 
several mechanisms are proposed. For example, valproate increases ovarian androgen 
production. It also can result in weight gain and insulin resistance, both risk factors for PCOD. In 
the liver, the drug can increase unbound testosterone. 
Epilepsy, for which valproate is widely used, is tipped to increase PCOD occurrence. Such 
association has not been established so far for bipolar disorder. 
Almost all patients who develop oligomenorrhea develop it in first year of treatment with 
valproate. 
Haematological effects 
Lithium can cause leucocytosis that can be therapeutically utilized in some cases of benign 
neutropenia related to clozapine use. This is not widely practiced. 
Around 10% of individuals taking carbamazepine will see gradual onset leucopenia in first 
3months of treatment. This is reversible on continued treatment or dose reduction. 
Thrombocytopenia is a dose-related effect of valproate and carbamazepine – a reduction in dose 
is required if bruising, or bleeding gums is noted. 
Neurological effects 
Fine tremor is a common benign side effect of lithium, and coarse tremor is a sign of toxicity. 
Propranolol can be used in treating lithium-induced fine tremor at therapeutic levels. 
Lamotrigine is generally well tolerated but can cause dizziness, ataxia, headache, sedation, 
tremor, and nausea. 
Topiramate can produce word finding difficulties (anomia) and poor concentration 
Vigabatrin, an antiepileptic with no significant antimanic efficiency, has been tried in some openlabel trials. It has a peculiar side effect of causing visual field defects.