Large oral doses of individual amino acids were given three or four times daily for periods of 1 week to schizophrenic patients, some of whom were maintained on iproniazid. Marked alterations in behavior in some patients were associated with the administration of l-methionine and of l-tryptophan.

Simple reaction times to auditory stimuli varied with the phase of the cardiac cycle in which the stimuli were presented, tending to be fastest to stimuli presented during the P-phase of the electrocardiogram. One hundred reaction times obtained from each of 56 men and women between the ages of 20 and 30 years were analyzed.

The effects of a pharmacologic dose of delta-9-tetrahydrocannabinol (A-9-THC) on the human circulatory system were investigated. Their relation to plasma drug levels, urinary catecholamine excretion, and psychic effects was observed. A-9-THC (0.3 mg. per kilogram) was administered orally to 8 male volunteers. Four subjects also received tracer amounts of C"4-l!.-9-THC. Recumbent and upright heart rate, recumbent mean arterial blood pressure, forearm blood flow, and calculated forearm conductance all increased significantly following drug administration. Significant shortening of ventricular pre-ejection period and attenuation or abolition of reflex venoconstriction in response to a deep breath were also seen. Mean arterial pressU1'e decreased transiently with head-up tilt and was associated with presyncope in 7 subjects, although cardioacceleratory response and forearm mtm'iolar constriction remained intact. Plasma levels of CILA-9-THC and its metabolites were maximal at 3 hours. Gastrointestinal absorption was 95 per cent complete. Urinary excretion of free epinephrine was significantly higher during the 6 hour period following A-9-THC admini5tration than during a similar control period. Free norepinephrine excretion was unchanged. Several of the cardiovascular effects seen appear to be consistent with increased sympathoadrenal activity. This suggests the possibility that augmented epinephrine secretion is in part responsible for these Circulatory changes.

L‐Dopa produced a significant reduction in recumbent and standing blood pressure in patients with neurologic or psychiatric disorders. The addition of an extracerebral decarboxylase inhibitor potentiated this effect. Reflex forearm arteriolar and venous constriction was present during therapy with L‐dopa alone or in combination with the decarboxylase inhibitor, but there was an attenuation of reflex forearm arteriolar constriction. It is suggested that the hypotensive effect of L‐dopa may be mediated through the central nervous system.