Cognitive Effects of Drug Abuse

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Cognitive Effects of Drug Abuse

• Kristi A. Sacco, Psy.D.
• Associate Research Scientist
• Department of Psychiatry,
• Yale School of Medicine

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Objectives of Talk

• 1. To become familiar with the purpose of
  neuropsychological assessments.
• 2. To understand how neuropsychological
  assessments pertain to the evaluation and
  treatment of substance abuse disorders.
• 3. To become familiar with the application of
  neuropsychological assessment data is used in
  substance abuse research.

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Freedman, 2003
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What is Neuropsychology?

• Study of brain-behavior relationships
• Involves performing manual tasks
• Provides information regarding functional
  implications of brain insults (e.g., tumor,
  infarct, surgery)
• Uses standardized assessment procedures

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Neuropsychological Evaluation
Can address a variety of neurologic conditions
including

• Traumatic Brain Injury (TBI)
• Dementias
• Cerebrovascular Accidents
• Metabolic and toxic encephalopathies
• Pre- and post-surgical conditions
• Medical, psychiatric, and neurologic disorders
  affecting central nervous system functioning.

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Neuropsychological Evaluation
Procedures typically incorporate measures of

• Intellectual functioning
• Academic skills
• Attention and concentration
• Information processing speed
• Learning and Memory
• Conceptual and problem-solving capacity
• Language
• Visuospatial abilities
• Sensory-perceptual functioning
• Motor performance
• Emotional adjustment/personality
• Response bias (effort and motivation)

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Neuropsychological Evaluation, Cont.

• -Intellectual functioning Wechsler Intelligence
  Scales
• -Academic skills Wechsler Individual
  Achievement Test
• -Attention and concentration CPT, Digit Span
• -Information processing speed Trails A
• -Learning and Memory CVLT, VSWM
• -Conceptual and problem-solving capacity - WCST
• -Language Vocabulary, COWAT (word fluency), BNT
• -Visuospatial abilities Rey Complex Figure Task
• -Sensory-perceptual functioning Seashore Rhythm
• -Motor performance Grooved Pegboard, Finger
  tapping
• -Emotional adjustment/personality MCMI, PAI
• -Response bias (effort and motivation) - TOMM

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Neuropsychological Evaluation
How are the results used?

• Confirm or clarify a diagnosis.
• Provide a profile of strengths and weaknesses to
  guide rehabilitation, educational, vocational, or
  other services.
• Document changes in functioning since prior
  examinations, including effects of treatment.

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Neuropsychological Evaluation, cont.

• Clarify what compensatory strategies would help.
• Result in referrals to other specialists, such as
  educational therapists, cognitive rehabilitation
  professionals, neurologists, psychiatrists,
  psychologists, social workers, nurses, special
  education teachers, or vocational counselors.

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Visuospatial Working Memory (VSWM) Task The
Dot Test

• The Dot test - adapted from previous studies of
  VSWM in non-human primates and schizophrenics
  (e.g. translational) Park and Holzman, 1992
  Williams and Goldman-Rakic, 1995 Keefe et al.,
  1995
• VSWM is dependent on prefrontal cortical dopamine
  function Williams and Goldman-Rakic, 1995
  Jentsch and Roth, 1999.

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Visuospatial Working Memory Task
Screen 1
Screen 2 Distractor Screen
The dot is presented to the subject for 3 sec.
Subject completes the tic-tac-toe during the 30
or 60 sec. delay.
Mouse pointer is kept in the center of this box
Screen 3
(30 or 60 Sec. Delay)
?
Subject has to click where the black dot was
located in screen 1
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Continuous Performance Test - X

• Test of sustained attention over extended (15
  min) period of time.
• Monotonous task requiring vigilance
• Also measures impulsivity, errors of omission,
  commission and variability.

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CPT

• On the screen in front of you letters will
  appear. You are to quickly press the space bar
  for any letter you see, except for the letter X.

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CPT Slide
R
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A
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S
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B
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V
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X
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Neuropsychological Impairment secondary to
Substance Abuse
Assessment of Substance Abusers

• Alcohol
• Cocaine
• Opiates
• Marijuana
• Ecstasy
• Polysubstance Abuse
• Nicotine

What are the effects of acute use, chronic use,
and abstinence on neuropsychological performance?
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Alcohol

• Because of its central nervous system depressant
  properties, mimics effects of tranquilizers and
  hypnotic drugs on neuropsychological functioning.
• Social Drinking
• Positive relationship between amount and
  frequency of consumption and mild cog impairments
• Decreased ST recall
• Subtle deficits in concept formation and mental
  flexibility (Macran et al, 1982)
• Chronic Use (Alcohol Dependence)
• Some contradictory findings (i.e., variations in
  aging, medical risk factors, sex differences,
  family history).
• Complex visuospatial ability
• Psychomotor speed
• Learned skills (i.e., arithmetic, language)
• Wernicke-Korsakoff syndrome vs. Alcoholic Dementia

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Alcohol, cont.

• Effects relative to
• Intake quantity,
• Duration of drinking, and
• Age (especially age at which drinking began).
• Binge drinkers are less susceptible to
  alcohol-related cognitive deficits than heavy
  chronic daily alcohol intake (Sanchez-Craig,
  1980).
• Abstinence Effects
• Detox effects within 1st 2 weeks, almost all
  cognitive domains show deficits.
• Past 2 weeks several months later, most will
  show marked improvements compared to baseline.
• As one ages, reversibility less obvious.

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Cocaine

• High characterized by euphoric rush
• Acute - positive experiences of cocaine use
• Increased alertness
• Increased arousal
• Increased sense of well-being and confidence
• Chronic Effects
• CT scan atrophy, evidence of white matter lesions
• Slowed mental processing
• Memory Impairments
• Decreased mental flexibity (Rosselli, Ardila,
  Lubansky, et al, 2001).
• Decreased retrieval of learned information
• Mild storage deficit (Mittenberg and Motta,
  1993).

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Cocaine, cont.

• Deficits relative to amount of use and duration
  of abstinence.
• Long-term use
• - Memory and concentration
• - Impaired executive functioning
• - Reduced retrieval efficiency
• - Mild storage deficit

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Opiates

• Acute
• Mental and physical sluggishness, (Walton,
  1994) paralleled by EEG slowing (Brust 2000).
• Personal neglect
• Few studies documenting cognitive effects of
  acute use.
• Chronic Use
• Decreased visuospatial and visuomotor performance
  (Carlin OMalley, 1996 Grant, Adams, Carlin,
  1978)
• Diffuse impairment with lowest performance on
  tasks requiring integration of different
  functions (Rounsaville, Novelly, Kleber, 1981).
• Overall, LT use of opiates has not been shown to
  severely impair cognitive functioning (Brust,
  2001 Lishman, 1981).

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Opiates, cont.

• Long-term Abstinence
• Mental flexibility, attention, and abstract
  reasoning returned to levels of non-users (Pav et
  al, 2002), however impulsivity remained at a
  deficit compared to nonusers.

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Marijuana

• Acute hallucinatory and reactive emotional states
  (Brust, 2000). Acute cognitive effects
• Time disorientation
• Transient memory loss
• Impaired attention
• Slowed visual processing
• Poor time perception
• Consequences for driving under influence
• Long Term effects (Findings are equivocal)
• Composite test scores on major battery of users
  vs. nonusers showed no differences (Colver
  King)
• Many studies looked at polydrug use, attempting
  to isolate effects of MJ.
• 10 Years of regular use
• Findings similar to early use, but general
  reviews suggest some instruments used may not be
  sensitive (Carlin OMalley, 1996).

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Ecstasy

• Deficits in memory functioning are most clearly
  identified across studies (Morgan, 2000 Parrot,
  2001).
• Lighter users
• Some studies suggest that lighter users may
  display unimpaired neurocognitive profiles (Fox,
  2001 Rycroft and Golding, 2002).
• These users complain of minor memory problems
  (Parrott, 2002).
• Chronic
• Poor delayed memory ability (Rodgers, 2000)
• Abstinence
• Limited research some suggestion for ongoing
  memory deficits.

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Polysubstance abuse

• Acute abstinence
• Within 1-2 weeks of abstinence, 50 demonstrated
• Slowing and impaired memory (verbal and visual)
• Visuoperceptual deficits
• Verbal deficiencies (McCaffrey Krahula, 1988).
• Risk of cognitive impairment is linked with age,
  poorer education, and medical problems.

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Nicotine

• Acute effects
• Smoking deprivation impairs cognitive
  performance, re-administering cigarettes reverses
  these deficits (Bell et al., 1999, Sacco et al.,
  2004)
• Generally improves performance in deprived
  smokers.
• Long-term effects
• Sustained abstinence suggests improvements in
  VSWM function in non-psychiatric control smokers
  (George et al., 2002).
• In contrast smokers with schizophrenia
  demonstrated a deficit over a period of sustained
  abstinence (George et al., 2002).
• Special populations
• Nicotine has been shown to have positive effects
  on disease-specific deficits in several
  neuropsychiatric diseases (Sacco et al, 2004 in
  press Newhouse et al., 2004), including
• Schizophrenia
• Major Depression
• ADHD
• Tourettes Disorder
• Alzheimers Disease

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Using Neuropsychological Assessment in Substance
Abuse Research

• Predictors of treatment outcome. (Dolan et al.,
  2004 Teichner, 2000)
• Cognitive rehabilitation
• Effects of treating substance abuse on cognitive
  deficits.

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Cognitive Function as a Predictor of Treatment
Outcome

• Cognitive dysfunction may include impulsivity and
  deficits in executive functions.
• This may impair treatment retention, leading to
  drop-outs/ relapse (Smith, McCrady, 1991)
• Cognitive abilities may predict treatment outcome
  for problem drinkers (Abbott and Gregson, 1981)
• Visual spatial working memory and executive
  functioning predict smoking cessation treatment
  success in subjects with schizophrenia compared
  to non-psychiatric controls (Dolan et al., 2004).
  
• Impairments in attention, mental reasoning, and
  spatial processing (MicroCog) decreased CBT
  treatment retention and abstinenc in cocaine
  abusers (Abromovitz, 2003)

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PFC-Dependent Neuropsychological Deficits Predict
Smoking Cessation Failure in Schizophrenics
Dolan, Sacco et al. (2004), SCZ Research, in
press.
p0.052
plt0.05
plt0.05
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Effects of Smoking Abstinence on VSWM in
Schizophrenic (n23) and Control (n29) Smokers
Smoking Status X Time F3.16, df2,62, plt0.05
Smoking Status X Time F6.11, df2,22, plt0.01
George, T.P. et al. (2002). Neuropsychopharmacolog
y 26 75-85.
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Summary

• Neuropsychological assessments are used to answer
  a variety of clinical questions
• These assessment techniques are often applied in
  a research setting.
• In substance abuse research, much evidence
  supports various aspects of cognitive deficits
  following drug use.
• Limitations in these findings include lack of
  well-controlled studies, including controlling
  for polysubstance use.
• Application of neuropsychological findings to
  substance abuse research can include identifying
  profiles for predicting treatment success and
  identifying changes following abstinence of
  substances of abuse.

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Future Research

• Longitudinal evaluation of cognitive function in
  substance abusers will help us sort out the
  following question of causality.

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Drug Abuse
Cognitive Deficits