In the absence of full understanding of the nature of anxiety neurosis, therapy must be, in part, symptomatic. Along with reassurance and efforts to comprehend the important aspects of the situation, most doctors are forced to use tranquillizing drugs. Careful clinical studies are, therefore, important.

In another paper, Jenner, Kerry and Parkin (1961) confirmed the views of earlier workers, Harris (1960) and Voelkel (1960) and others that methaminodiazepoxide is an effective agent in relieving anxiety in neurotic patients. That study was a blind controlled comparison of methaminodiazepoxide against lactose, but gave no indication of its value as compared with other drugs. The present paper is a comparison of methaminodiazepoxide (Librium, Roche) and amylobarbitone. The latter drug was felt to be one of the best known and most reliable drugs used in psychiatry for the treatment of anxiety. Raymond, Lucas, Beesley, O'Connell and Fraser-Roberts (1957) compared it very favourably with benactyzine, chlorpromazine, meprobamate, sedaltine and lactose. In that trial amylobarbitone was the only drug significantly better than lactose.

The theoretical framework developed by Eysenck (1955) to account for individual differences in motor and other types of performance has, as its main postulate, the statement that extraverts are characterized by high rates and introverts by low rates of inhibitory growth. An extension of this framework (1957) has allowed a link to be made between personality theory and the theory of drug action, since it has been proposed that depressant drugs increase cortical inhibition and so produce extraverted behaviour patterns, while the opposite is true of stimulant drugs. A test of this postulate by Eysenck, Casey and Trouton (1957) suggested that it was essentially confirmed when applied to motor performance. Dextro-amphetamine sulphate was found to improve and sodium amylobarbitone to depress pursuit rotor performance at all stages of practice. It was concluded that the effect of sodium amylobarbitone was to increase the two inhibitory factors recognized by Hullian learning theory, viz. conditioned inhibition (SIR) and reactive inhibition (IR).