Caudate nucleus morphology in tardive dyskinesia

Caudate nucleus volume in individuals at ultra-high risk of psychosis: a cross-sectional magnetic resonance imaging study

The aim of the present study was to investigate whether volumetric abnormalities of the caudate nuclei predate the onset of psychotic illness. Caudate nuclei volume (CNVs), excluding the tail, were measured using region-of-interest (ROI) tracing of magnetic resonance imaging (MRI) scans acquired on a 1.5T scanner. Subjects included 39 individuals deemed at ultra-high risk of psychosis who converted to psychosis (UHR-P) after initial MRI scanning; 39 matched individuals at ultra-high risk who did not convert to psychosis (UHR-NP); and 39 matched healthy controls. All subjects were neuroleptic-naïve. After adjusting CNVs for intracranial volume (ICV), univariate analyses of variance and repeated measures analyses of variance were undertaken to examine the relationship of CNVs to psychosis transition and to family history of psychosis. Pearson's correlations were used to investigate the relationship of psychopathological scores to CNVs. CNVs did not differ significantly between UHR individuals and healthy controls, and there was no significant difference between converters and non-converters to psychosis. In the UHR group, presence of family history of psychosis was not related to CNVs. There was no correlation between CNVs and either positive or negative symptoms of schizophrenia. Significant associations were found between larger CNV and increased errors on a spatial working memory task but better verbal fluency performance. These data suggest that the caudate is macroscopically normal prior to illness onset, while the relationship to tasks of executive function may implicate the caudate together with its connections to prefrontal regions. Future research should examine changes longitudinally together with analysis of shape to assess subregions of the caudate that connect with prefrontal cortex.

Proton magnetic resonance spectroscopy study of dyskinesia patients

Oral dyskinesias may occur spontaneously or be induced by medications such as antipsychotics and antidepressants. In this study, single voxel proton magnetic resonance spectroscopy was used to compare metabolite levels in the striatum for (1) 12 patients with drug-induced tardive dyskinesia (TD), (2) 12 patients with spontaneous oral dyskinesia (SOD), (3) 8 antidepressant-treated patients without TD, and (4) 8 control subjects. Statistically significant reductions in the choline/creatine (Cho/Cr) ratio were measured for the drug-treated patients with TD (-13%, P = 0.020) and SOD patients (-12%, P = 0.034) relative to control subjects. In comparison with antidepressant-treated patients without TD, drug-treated patients with TD showed a non statistically significant reduction in Cho/Cr (-11%, P = 0.079). All other metabolite ratios (N-acetylaspartate (NAA)/Cr, myo-inositol (mI)/Cr, glutamine + glutamate (Glx)/Cr, macromolecule + lipid (MM+Lip)/Cr, NAA/Cho) were unaffected by either type of dyskinesia. The observed Cho/Cr reduction in dyskinesia patients suggests decreased membrane phosphatidylcholine turnover, which provides free choline as precursor of molecules responsible for cellular signal transduction.

Selective serotonin reuptake inhibitor-related extrapyramidal symptoms in autistic children: a case series

Abnormal movements occur rarely with selective serotonin reuptake inhibitors (SSRIs). This report describes four consecutive autistic children who developed extrapyramidal side effects (EPS) following SSRI exposure. Videotapes, physician notes, and parental interviews were used retrospectively to rate symptoms on the Extrapyramidal Symptom Rating Scale. Findings suggest that EPS is a potential complication of SSRI treatment in autistic children.

Early extrapyramidal side-effects as risk factors for later tardive dyskinesia: a prospective study

OBJECTIVE

To determine whether acute neuroleptic-induced parkinsonism and akathisia were risk factors for the later development of tardive dyskinesia (TD) in patients on typical neuroleptics.

METHOD

Of 100 subjects examined for parkinsonism and akathisia after the initiation of typical neuroleptic medication, 78 were followed up for TD after a mean 41.2 months.

RESULTS

Nine (11.5%) subjects were diagnosed with TD, predominantly manifesting as oro-facial dyskinesia. They had greater severity of parkinsonism and akathisia at baseline, and a larger neuroleptic load, than those who did not develop TD. On regression analyses, parkinsonism at baseline was a significant predictor of later TD. Examined independently of parkinsonism, akathisia severity at 2 weeks was also a significant predictor of later TD.

CONCLUSIONS

Acute drug-induced parkinsonism and akathisia are both predictors of TD, with parkinsonism having greater predictive value. Acute and tardive extrapyramidal syndromes may share vulnerability factors.

Antipsychotic drugs and neuroplasticity: insights into the treatment and neurobiology of schizophrenia

This paper reviews the evidence that antipsychotic drugs induce neuroplasticity. We outline how the synaptic changes induced by the antipsychotic drug haloperidol may help our understanding of the mechanism of action of antipsychotic drugs in general, and how they may help to elucidate the neurobiology of schizophrenia. Studies have provided compelling evidence that haloperidol induces anatomical and molecular changes in the striatum. Anatomical changes have been documented at the level of regional brain volume, synapse morphology, and synapse number. At the molecular level, haloperidol has been shown to cause phosphorylation of proteins and to induce gene expression. The molecular responses to conventional antipsychotic drugs are predominantly observed in the striatum and nucleus accumbens, whereas atypical antipsychotic drugs have a subtler and more widespread impact. We conclude that the ability of antipsychotic drugs to induce anatomical and molecular changes in the brain may be relevant for their antipsychotic properties. The delayed therapeutic action of antipsychotic drugs, together with their promotion of neuroplasticity suggests that modification of synaptic connections by antipsychotic drugs is important for their mode of action. The concept of schizophrenia as a disorder of synaptic organization will benefit from a better understanding of the synaptic changes induced by antipsychotic drugs.

Decreased choline acetyltransferase immunoreactivity in discrete striatal subregions following chronic haloperidol in rats

Neuronal loss within the basal ganglia has been hypothesized to play a role in movement disorders (e.g., tardive dyskinesia) that often occur following chronic neuroleptic treatment. Previous studies in animal models have provided some support to this possibility, but have not assessed regionally specific changes after chronic neuroleptic administration. The present study examined whether counts of neurons containing acetylcholine, described as large aspiny type II neurons, were altered in subregions of the corpus striatum and nucleus accumbens following chronic haloperidol administration in rats. Rats were administered haloperidol decanoate (21 mg/kg, i.m.) or vehicle every third week for 24 weeks. Following 4 weeks of withdrawal from the drug, predefined regions were examined for choline acetyltransferase (ChAT) immunoreactive (ir) cells. Compared to the vehicle group, the haloperidol group showed significant reductions in ChAT-ir cell counts in the ventrolateral striatum, nucleus accumbens core, and nucleus accumbens lateral shell. No significant differences were found in the other regions examined: dorsolateral striatum, dorsomedial striatum, ventromedial striatum, nucleus accumbens medial shell, and horizontal limb of the diagonal band. These findings indicate that there may be regionally specific alterations in ChAT-ir cells following chronic haloperidol treatment, supporting previous hypotheses of striatal cholinergic cell loss resulting from chronic neuroleptic treatment. More importantly, the regions affected (ventrolateral striatum and nucleus accumbens) are critical in the regulation of oral movements, thus suggesting that alterations in cholinergic cell activity, and perhaps actual loss of cholinergic cells in these regions, may be important in the manifestation of late-onset oral dyskinesia.

Case study: childhood-onset tardive dyskinesia versus choreoacanthocytosis

A male adolescent presented with aggression, depressed mood, and severe movement disorder that developed at age 5 after exposure to neuroleptics. Evaluation revealed acanthocytes in his blood, which led to a differential diagnosis of tardive dyskinesia versus choreoacanthocytosis. However, this is unusually young age of onset for these conditions. Differential diagnosis, medication management of the movement disorder, and pathophysiological mechanisms in tardive dyskinesia and choreoacanthocytosis are discussed.