Borderline Intellectual Functioning

Borderline Intellectual Functioning (BIF) is not a psychiatric disorder, but rather a description of people who function between average cognitive levels and Intellectual Disability (ID). Although persons with BIF may function at a high-enough level not to be diagnosed with an intellectual disability, they nevertheless score in a low intelligence quotient (IQ) range and may experience significant challenges as a result. BIF may be caused by genetic factors or maternal complications during pregnancy, but can also result from childhood neglect or exposure to toxins such as lead. Individuals with BIF face increased risks of physical health problems, psychiatric disorders, and substance abuse. Low intellectual functioning can seriously threaten both children and adults’ ability to succeed in daily life, potentially leading to poverty and other significant stressors.

Although as much as 13.6% of the population may qualify as having borderline intellectual functioning, the condition has a low recognition rate. People with BIF may try to mask cognitive challenges with an appearance of normalcy, and in any event may not qualify for public services without a diagnosis of ID. As a result, people with BIF are an under-recognized and vulnerable group that faces increased obstacles and risks.

Signs of Borderline Intellectual Functioning

  • Decreased intellectual functioning in areas such as reasoning, problem solving, planning, abstract thinking, judgment, academic learning, and learning from experience.
  • Difficulty adapting to changes or learning new skills.
  • Difficulty achieving independent living, executing daily life activities, and participating with others in social situations.
  • Difficulty managing emotions and aggression, with moods swings and low frustration tolerance.
  • Naiveté, gullibility, or poor common sense.
  • Social inappropriateness.
  • Poor ability to concentrate and slow response time. General disorganization.

How BIF Might Impact Behavior

Persons with BIF frequently struggle to succeed in school as children and maintain employment as adults. Adults may struggle in workplaces where they receive no accommodations for challenges in concentrating, following complex instructions, multitasking, and exercising independent judgment. Individuals with BIF are more likely to succeed when supported and given concrete, predictable tasks.

Because individuals with borderline intellectual functioning face many challenges yet also receive little recognition and few services, many experience depression, anxiety, and low self-esteem. Persons with BIF may receive ADHD or learning disorder diagnoses in partial recognition of their symptoms, yet these diagnoses do not fully capture the impact of borderline intellectual functioning in many realms of life.

Some research has demonstrated correlations between low IQ levels and crime; however, any related conclusions are complicated and limited by the many sociological factors that contribute to why individuals commit crime. Criminal justice advocates have argued that cognitive impairment should be a significant mitigating factor in conviction and sentencing decisions, as persons with reduced intellectual functioning may have reduced understanding of and culpability for their actions in certain circumstances. Furthermore, persons with BIF have been shown to be  vulnerable to exploitation in criminal proceedings, possibly manifesting in outcomes such as in false confessions or unwise plea agreements.

Recent Developments

Several changes were made to the definition of Borderline Intellectual Functioning in the DSM-5, the most significant of which was the removal of the specific IQ bracket from 71-84. There is now no specific IQ range attached to the condition: BIF is defined as when an individual’s reduced intellectual functioning is the focus of clinical attention or has an impact on the individual’s treatment or prognosis.

Modern research and treatment programs have revealed the importance of early intervention in improving outcomes for children experiencing BIF. However, children with BIF are less likely to be identified at a young age than those diagnosed with an intellectual disability, and these individuals’ struggles may be attributed to lack of motivation or effort. These children’s difficulties may become more apparent in a school setting, but many individuals with BIF may still not receive critical interventions if they are not diagnosed with an intellectual disability.

The connection between lead poisoning in children and low intellectual functioning has been the subject of recent research. Throughout the twentieth century, many American children, especially those of low socioeconomic status, were frequently exposed to lead, with many experiencing poisoning and reduced intellectual functioning as a result. The epidemic proportions of this problem were not well understood until the late 1960s and 1970s. Although the law and housing conditions have since improved, many older persons experienced harmful lead exposure, and the problem persists in American communities with high rates of poverty and environmental pollution potentially leading to decreased intellectual functioning.

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Please Note

The CCRI worked with the  Bazelon Center for Mental Health Law to produce this Fact Sheet in 2017. Please note that this document only offers an overview and simply serves as a starting point in considering the impacts of a particular condition on an individual. This Fact Sheet does not provide the level of detail, citations, medical terminology, or full diagnostic criteria that an expert or medical professional would need to make a diagnosis or that a lawyer would need to have to advocate most effectively on behalf of her client.