A “vicious circle” hypothesis is put forward for the common kind of somatization which forms the basis of the DSM's “somatization disorder.” Two compounding mechanisms are seen to be operative: (1) a failure of higher order inhibitory systems involved in the “medial pain system”; (2) amplification of stimulus intensity produced by the effect of attention. Attentional failure is produced not only by social factors but also by failure of sensory intensity modulation consequent upon (1). The argument focuses on data from borderline patients in whom the unusual prominence of pain may be due, at least in part, to incompetence of the “medial pain system.” This is reflected in enlarged P3a components of the event-related potential suggesting diminished inhibitory function involving prefrontal connections. Two studies are briefly presented in summary form suggesting that somatization may be ameliorated by a form of therapy which focuses on “inner” material as a means of overcoming “stimulus entrapment.”