Inmate populations have been found to have mental health problems and substance abuse much higher than non-incarcerated populations. Caring for incarcerated patients is problematic, given the limitations on access to healthcare services within detention facilities. A case report of a patient with psychomotor agitation and psychoactive substances use, prone to hetero and self-aggression, is presented. The patient was treated for a month in a Mexican state detention center by nursing students, under supervision and pedagogical support. Using the nursing process, focused on psychosocial health needs, six priority diagnoses were identified: anxiety, ineffective health maintenance behaviors, acute confusion, risk of self-directed violence and violence directed at others, as well as discomfort. Based on these diagnoses, care plans using cognitive stimulation was carried out with the goals of decreased anxiety, increased self-care, increased self-responsibility, better anger control, management of hallucination. The cognitive stimulation was a primary intervention that helped with other interventions to achieve holistic goals, such as improving hygiene. Improvements in the patient’s general ability to function led to, among other aspects, the release of solitary confinement and adaptation to social environment of the prison. Patient improvements reflect the importance of professional nursing care in mental health care in correctional healthcare.