Borderline intellectual functioning: an update

Borderline intellectual functioning (BIF) is a descriptive v-code that is often used, especially in forensic settings, as if it were a full-fledged disorder. Various historical and other aspects of this classification are reviewed, and commentary is made on the question of whether to upgrade BIF to a regular psychiatric category, or to eliminate it by folding it into an already recently expanded category of intellectual developmental disorder (IDD).

Full-scale intelligence quotient (IQ) is an outmoded concept that is decreasingly being used. For example, DSM-5 states that measures of 'executive functioning' (reasoning, planning, consequential thinking, attention, self-regulation, and so on) are often more meaningful that full-scale IQ as diagnostic indicators of IDD. Even the definition of BIF in DSM-5 no longer specifies an IQ score range.

BIF is a descriptive v-code (rather than a typical psychiatric category), which started out as a sub-type of IDD (formerly mental retardation or intellectual disability) but morphed into its current status when the IQ ceiling for IDD was changed from minus one standard deviation (85) to minus two standard deviations (70). It has been suggested that, as people with BIF often have adjustment problems, the BIF category be elevated to the status of a formal psychiatric disorder. In this article, a contrary opinion is expressed, namely that the BIF category be dropped.