Clozapine for tardive dyskinesia in adolescents.

Thousands of adolescents use neuroleptic drugs over extended periods of time for a wide range of mental disorders. One of the most severe adverse effects of neuroleptic drugs is tardive dyskinesia (TD), for which no successful treatment is currently available. Clozapine is a known atypical neuroleptic drug with few extrapyramidal side effects. It has been suggested that clozapine may be beneficial for the treatment of tardive dyskinesia in adolescents. However, the efficacy of the drug in adolescents is unknown. This report describes the beneficial effect of clozapine on tardive dyskinesia in two adolescents with schizophrenia.

[Dilantin toxicity as a possible cause of major depression].

Diphenylhydantoin (D; Dilantin) is widely used in neurologic and psychiatric practice for treating convulsive disorders. D overdosage and poisoning may cause behavioral disturbances, such as schizophreniform and delusional states. To the best of our knowledge, D has been linked with mood disorders in just 1 documented case. We report a 70-year-old woman who developed major depression as a complication of D intoxication. Treatment with folic acid led to complete recovery. We believe that D causes depression by lowering folic acid blood levels by a biochemical mechanism. We suggest that levels of D and folic acid be monitored continually all patients treated with the drug.

Cerebral microcirculation: heterogeneity of pial arterial network controlling microcirculation of cerebral cortex.

Analysis of the functional behaviour of pial arterial ramifications feeding small areas of the cerebral cortex of rabbits uncovered well-defined heterogeneity of vascular responses during development of functional hyperemia. In the network of the smaller pial arteries, under 100 microns in diameter, the most active segments, the sphincters of offshoots of smaller arterial branches from larger trunks and the precortical arteries just before their penetration as the radial arteries into the cerebral cortex, have been discovered. The frequency of their dilatation was found to be higher, the latent periods of the vascular responses significantly shorter, and the degree of vasodilatation greater than of the adjacent arterial segments. An abundant amount of cholinergic nerve plexuses (containing the cholinesterase) was found in the walls of these active vascular segments, and microapplication of atropine resulted in a considerable decrease of their dilatation. These experimental results indicate the involvement of the cholinergic neurogenic mechanism in the functional vasodilatation, as distinct from the largely accepted effect of the humoral mechanism accomplished by diffusion of active vasodilatory substances from tissue elements to the walls of the feeding arterial branches.