Based on the “normal curve,” the distribution of various psychological characteristics in the general population, nearly 23 out of 100 individuals can be classified as having below average intellectual functioning—IQ’s that range from 70 to 89 but fall above what is generally considered mild mental retardation.
Borderline Intellectual Functioning is a significant correlate and risk factor for the development of a broad spectrum of neuropsychiatric disorders treated by psychiatrists and, more specifically, is quite common among patients with autistic and psychotic spectrum disorders.2,3 It is also a significant risk factor for less favorable treatment outcomes. As well, it is a robust predictor of limited educational/vocational attainment and is associated with persistent problems with adaptive coping.
Psychopharmacologic interventions may need to be modified in keeping with the reduced cognitive capacities of these patients. In many cases, certain interventions may be contraindicated, including some forms of psychodynamically-based psychotherapy.
Many patients with Borderline Intellectual Functioning can be expected to have difficulty comprehending the rationales for various treatment plans/recommendations, leading to lowered adherence/compliance. Hence, treatment interventions in this subpopulation should be modified to take into account the cognitive limitations of Borderline Intellectual Functioning.
Because of its high prevalence within various neuropsychiatric groups and potential for significantly affecting treatment planning and outcome, the DSM-IV Task Force should consider removing Borderline Intellectual Functioning as a V code and including this designation as a possible separate axis, specifier, and/or part of a “dimension” germane to cognitive competence/disability.
When in doubt about such a designation in a particular case, referral to a psychologist for cognitive/neuropsychological testing and assessment of adaptive capabilities/functioning would be appropriate.
1. Frances A. Advice to DSM-V: Change deadlines and text, keep criteria stable. Psychiatric Times. 2009;XXVI:1,7-8.
2. Wechsler D, Coalson DL, Raiford SE. WAIS-IV technical and interpretive manual. San Antonio, Texas, Pearson; 2008.
3. Harvey, P, Keefe R. Clinical neuropsychology of schizophrenia. In: Grant I, Adams K, eds. Neuropsychological Assessment of Neuropsychiatric and
Neuromedical Disorders. New York, Oxford, 2009;507-522.