Forensic Assessment of Substance Use Disorders

Dr. John Matthew Fabian has an extensive history of assessment of substance use disorders in criminal litigation as both a forensic psychologist and neuropsychologist. Dr. Fabian has special interest on the clinical/forensic neuropsychological evaluation of both the acute effects during intoxication and long-term effects of substances on brain/behavior functioning in criminal and civil forensic contexts. Substance use disorders are the most prevalent diagnosis in criminal forensic offender populations. The forensic evaluation and educational testimony of substance use disorders is relevant in a number of psycholegal assessments including the following:

  1. Competency to stand trial and waive Miranda rights
  2. Not guilty by reason of insanity/settled insanity, diminished capacity/mens rea, and criminal intent
  3. Mitigation, dual diagnosis, and substance effects on acute brain functioning and long term brain damage/cerebral dysfunction
  4. Substance effects on consent to sexual activity/memory formation/alcohol memory blackouts/confabulation/false memory
  5. Substance use disorders and parental fitness and child custody evaluations
  6. Substance use disorders and effects on criminal violent and sexual behaviors

Noted substances that have significant effects and nexus in their relationship with criminality and brain damage/dysfunction:

  1. Crystal Methamphetamine
  2. Toluene spray paint
  3. Phencyclidine PCP
  4. Alcohol
  5. Cocaine
  6. Benzodiazepines
  7. Opioids

Substances have a significant detrimental effect on emotional, behavior, and cognitive functioning. The risk of dual diagnosis and having co-occurring other mental health and neurological disorders is substantial in criminal forensic cases. Violence may share many of the same underlying mechanisms as substance abuse, given the comorbidity and commonalities in behavioral dimensions, including personality disorders with neurobiological underpinnings.

Neuropsychological dysfunction consistently characterizes both drug abuse and violence and may contribute to traits often cited as precursors to both, for example, impulsivity, poor decision-making ability, disinhibition, and inability to assess consequences. Deficits in executive cognitive functioning, especially those controlled by the prefrontal cortex are implicated in substance abusers with violent behavior.

Other areas of neuropsychological deficit implicated in substance use disorders include memory, attention, processing speed, working memory, and visual spatial functioning.