These data suggest that a low plasma TRYP/LNAA ratio is associated with susceptibility to anxiety, antisocial-type personality characteristics, and an early age of onset for alcoholism. In contrast, a high plasma TRYP/LNAA ratio is associated with a later onset of alcoholism and dysphoria.

Thyroid hormone produces metabolic effects similar to those of stimulation of noradrenergic receptors. It has been reported, however, that norepinephrine turnover is reduced during thyrotoxicosis and that beta-noradrenergic receptor number is increased. Metabolic effects of thyroid hormone may therefore reduce noradrenergic activity. We examined effects of thyroid hormone administration or production of hypothyroidism with methimazole on receptors associated with regulation of noradrenergic function. Treatment with thyroid hormone increased beta-receptor binding, increased alpha-2 receptor binding, and decreased desipramine binding, opposite to effects of hypothyroidism produced by methimazole. Heart was more sensitive than brain to these effects. These data are consistent with reduced noradrenergic activity during hyperthyroidism, possibly mediated by an increase in autoreceptor function.

The authors investigated preattentive filtering assessed by P50 gating in nine participants with antisocial personality disorder (ASPD) and seven with adult-onset antisocial behavior (AAB). Relative to 15 comparison subjects, gating was impaired in ASPD, suggesting abnormal pre-attentive filtering in pathological impulsivity.

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Panic patients who continued treatment (N = 12) did not have symptom scores significantly different from those of patients who declined or discontinued treatment (N = 12) but they did have lower pretreatment MHPG levels. Continuing in treatment may itself cause selection bias for biochemical variables under study.