AbstractThis paper discusses the possible role of neurological dysfunction in the frequent treatment-resistance of dual diagnosis patients. Through case vignettes, the complex treatment process of three dual diagnosis patients is presented. Each case demonstrates how in addition to both psychiatric and substance abuse problems, the patients also experienced neurological difficulties that made treatment even more complicated. The authors suggest that treatment providers should carefully screen for neurological disorders among this patient population. Attending to such comorbid difficulties in addition to patients' psychiatric and substance abuse problems may sometimes play a pivotal role in enabling patients to attain abstinence. The authors also speculate concerning the role of neurological dysfunction in the etiology of the dual diagnosis syndrome in at least a subgroup of dual diagnosis patients.