Abstract The nature of the therapeutic process was studied during a double-blind, multidimensional study of treatment with haloperidol in a group of acute schizophrenics. The data indicated that changes in social avoidance behavior might be a primary indicator of neuroleptic action. The use of an anticholinergic anti-Parkinsonism agent seemed to adversely affect these changes. It was noted that cognitive dysfunctions probably consisted of a “primary” drug-resistant element, originating perhaps in developmental defects of cognitive structure, and a “secondary” drug-sensitive element, which seemed to be a reflection of the superadded psychotic processes of decompensation. The drug-sensitive aspects of social and cognitive-integrative dysfunctions and indicators of arousal disturbance such as sleeplessness seemed to be fundamentally related and suggested a neurobiological hypothesis of neuroleptic action centered around cholinergic suppressor mechanisms in the brainstem and limbic system. Other findings of interest included the observations that patients reacting with dysphoric mood to neuroleptic treatment showed a less favorable pattern of therapeutic response and that overt aggression showed a diurnal variation which seemed internally determined. An analysis of the residual deficits after six months of treatment suggested that the patients had considerable problems in initiating and structuring social relations and organizing thoughts in terms of abstract principles. A developmental hypothesis was proposed to explain these observations.