Productive mental disorders (PMD) are the result of pathological mental activity. Alongside with deficient disorders PMD are the main characteristics of post-traumatic disturbances of consciousness. PMD can be represented by different types of excitation, mistaken judgments (including paranoidal ones, confabulations, false orientation), false perception (psychosensory, in particular, illusory and hallucinatory phenomena) and affective disorders. Occurrence and signs of PMD were studied in 417 patients with brain injuries and their consequences. It was found that occurrence of PMD in clear consciousness (in form of delirium, confusion etc) is often a sign of deterioration of cerebral and/or somatic situation and requires urgent diagnostic and therapeutic measures. In another situation with PMD being revealed during emergence from coma, they are regarded as a prognostically favorable sign and require some correction only in case of long-term (more than 1-3 weeks) course. It was determined that PMD are characterized by: (a) a gradual (after emergence from unconsciousness) aggravation and complications of clinical symptoms till achieved orientation in the surroundings with their possible partial or complete regress; (b) the highest frequency and intensity with prevailed signs of dysfunction of any of cerebral hemispheres and the lowest frequency in case of relatively symmetric bilateral and profound brain damage; b) a great variety and severity in adult patients (compared with children and elderly). Irritation of different brain structures and their disconnection as well as pathological neuroplasticity in prolonged forms - are considered the basis for PMD occurrence.