Bethesda Marriott, Bethesda, Maryland
June 4-5, 2003
Debbie Grossman, M.A. and Lisa Onken, Ph.D. under DCNDBT
On June 4-5, 2003, NIDA convened a 1 1/2-day workshop to discuss the state of the science related to treatment for cognitively impaired drug abusers. While there are currently many efficacious interventions available for drug addicted individuals in treatment, most do not consider the potential for cognitive impairment that may accompany chronic drug use and HIV infection. Many commonly utilized drug addiction and HIV-risk reduction interventions, which are cognitive-behavioral in their approach, assume certain basic cognitive capacities and abilities that may be absent, or impaired, in chronic drug abusers who may also be HIV-positive. Drug abusers with cognitive impairments may not be benefiting optimally from existing treatments. The purpose of this meeting was to discuss how addressing cognitive deficits in drug abuse treatment might lead to improved treatment response and outcome. Since there has not been considerable research done in this area, meeting participants came from varied backgrounds and areas of expertise, including basic neuroscience, cognitive dysfunction/ rehabilitation and drug abuse treatment. The meeting participants presented data from their area of expertise and recommended future steps to facilitate research in this area.
Prefrontal Cortex: The prefrontal cortex (PFC) provides an infrastructure for synthesizing a diverse range of information that lays the foundation for complex forms of behavior. Executive control, which is involved in the selection of goal related relevant stimuli is represented in the PFC. Tasks requiring greater control, require increased PFC function. If the PFC is damaged, components of complex behavior may remain in tact, but coordination of components may be compromised. PFC damage compromises critical skills, such as communication, reasoning, and planning, while automated systems dominate. PFC damage also increases distractibility, so that impaired persons cannot sort relevant from non-relevant information.
Drugs of abuse may be associated with structural and functional abnormalities in areas of the brain associated with executive functioning. These impairments may play a role in the development of addiction and undermine attempts to stop abusing drugs. Understanding how these abnormalities are related and their role in drug abuse could potentially contribute to the development of more appropriately targeted treatment interventions.
Consequences of Drug Abuse and HIV to Brain Functions: Little research has been done on understanding the neurocognitive effects of substances of abuse other than alcohol. Studying the impact of drug abuse on cognitive functioning brings about an increased research challenge due to a variety of factors, such as co-occurring use of multiple drugs, variations in drug strength, variations in drug purity, multiple routes of administration, and increased risk of HIV. However, research findings to date have reported that a substantial number of drugs addicted and HIV-positive patients show cognitive difficulties in several domains that could negatively impact their ability to benefit from addiction treatments. Information was presented that shows that chronic drug use and HIV infection may lead to global or distinct patterns of cognitive impairment.
Early clinical observations and studies examining cognitive impairment in heavy users of cannabis concluded that there was little evidence of gross cognitive impairment from chronic use. However, more recent studies employing improved methodology and more sensitive tests report that acute intoxication with cannabis clearly produces cognitive impairment of memory, attention, temporal processing and psychomotor performance. It is less clear, however whether cognitive functioning can recover after quitting or reducing cannabis use. Variable findings have been reported across studies on whether deficits are reversible in long-term users after quitting.
Mild to moderate levels of cognitive impairment are found in HIV positive patients. Although various patterns of dysfunction exist, the cognitive domains mostly impaired are learning and attention. HIV-related brain dysfunction is associated with impaired performance of daily tasks and poor life functioning and may influence compliance with treatment. Many confounding factors may influence cognitive function in AIDS patients, including drug abuse, age, education, and nutritional status. There may be an additive effect of HIV and drugs of abuse.
Neuropsychological evaluations of substance abusing adolescents suggest that use and withdrawal may differentially impact neurocognitive functioning, with heavy use leading to learning, retention, and attention difficulties, and withdrawal leading to problems with visuospatial functioning. Findings regarding drug use in adolescents include: nicotine modestly reduces cognitive flexibility in adolescents; marijuana shows decrements in learning, attention and cognitive flexibility, however these decrements may resolve within 30 days of abstinence; heavy use of stimulants is associated with slower information processing and poor attention; MDMA produces dose-related deficits in learning and memory, working memory, attention, processing efficiency, planning and reasoning and inhibition; inhalants are most damaging to the CNS and show global deficits in intellect, attention, perception, and cognitive flexibility; PCP produces global cognitive impairment; Ketamine shows persisting episodic and semantic memory impairments; opiates are not generally associated with persistent cognitive deficits; and h allucinogens have not been studied in adolescents.
Impairment associated with cocaine and opiates in adults at treatment entry is prevalent and clinically significant. Cocaine abusers show moderate but significant neurocognitive impairments in visuo-motor performance, visuo-spatial abilities, psychomotor speed, manual dexterity, verbal learning and memory, attention, executive control, cognitive flexibility, non-verbal problem solving, abstracting ability. Opiate addicts demonstrate deficits in tests of fluid cognitive abilities, memory and tapping tests. They also exhibit a tendency to choose small, immediate rewards over larger delayed rewards. Less apparent deficits are seen in attention or decision-making with opiate addicts.
Administration of nicotine is known to sharpen attention and slightly enhance memory. In preliminary studies, the cognitive enhancing properties of nicotine served to counterbalance or functionally overcome the negative effects observed in chronic substance abuse. A study examining the effects of acute nicotine administration on neurophysiological efficiency (the capacity to effectively utilize accurate information while ignoring interfering information), showed that increased nicotine improved reaction time (in controls, alcoholics, alcoholic/stimulants abusers, and stimulant abusers), vigilance (in alcoholics, but not in controls, alcoholics/stimulant abusers, or stimulant abusers), and visual-spatial attention (in alcoholics and controls).
Treatment of Cognitive Dysfunction in Other Disorders: Individuals possessing cognitive deficits related to disorders other than substance abuse has been successfully treated. Approaches to restoring cognitive ability and functioning in other disorders were presented to facilitate discussion about whether these approaches might have some application for drug abuse treatment.
A program for schizophrenic patients employing neurocognitive enhancement therapy with work therapy (NET + WT) was compared to work therapy alone (WT). NET included computer-based cognitive training on attention, memory and executive function tasks, an information-processing group, and feedback on cognitive performance in the workplace. Work therapy included pay for jobs at a medical center (mail room, grounds, library) with accompanying supports. Patients receiving NET + WT showed greater improvements of executive function, working memory, and affect recognition. Efficacy may result from a synergy between NET, which encourages mental activity, and WT, which allows a natural context for mental activity to be exercised, generalized, and reinforced. The cognitive training, led to activation in brain function, which further led to normalization.
A comprehensive day treatment for persons with traumatic brain injury (TBI) been shown to increase independence and decrease level of care. Key elements of this intensive intervention are: a cognitive/behavioral approach; an interdisciplinary team; training in community resources; an emphasis on self-awareness of strengths and weaknesses; low staff to patient ratio; family involvement; vocational and independent living trials; systematic outcome assessment; supported risk-taking and feedback; and cognitive rehabilitation. Cognitive rehabilitation is only one aspect of this approach. Improvement from cognitive rehabilitation alone would not generalize or be maintained in everyday life unless other areas, such as family involvement are addressed as well. Group treatment is particularly important in this population because the peer interaction provides feedback to increase self-awareness of deficits, support to reduce distress, and opportunities to practice social skills and emotional coping skills. One-to-one therapy fail to address these issues effectively.
Adults with ADHD have been successfully treated with a metacognitive remediation approach. The goal is to make cognition and behavior conscious. This approach assumes neuropathways are functionally disconnected which leads to inactivation or insufficient engagement of frontal and prefrontal lobes. Reconnection of these pathways by alternative routes constitutes a logical remedial approach in the treatment of ADHD. New connections are forced through complex multi-dimensional stimuli, which expand access to a reservoir of intact executive function. This approach requires a person to understand a personal metaphor by utilizing a mixture of visual imagery, symbol systems, and emotional valence, thus engaging a complex network of higher cortical regions. Metacognition forges neurointeractions while heightening subjective awareness.
Treatment of Drug Abusers with Cognitive Deficits: For substance abusers to benefit from psychological treatment, they must be capable of attending to and receiving new information, integrating it with existing information stores, and translating this input into more concrete behavioral change. Many widely used treatments include psychoeducational or cognitive behavioral components which require goal setting and planning ability, sustained attention, response inhibition, skill acquisition, and problem-solving capability. These are the same cognitive abilities most impaired in many drug abusers. In addition, there is a high prevalence of HIV infection and comorbid psychiatric disorders, like ADHD and antisocial personality disorder in drug abusers. These co-occurring disorders independently contribute to cognitive impairment and place an additional burden on the cognitive deficits that already exist due to substance abuse. The efficacy of many behavioral interventions thus may be inadequate for impaired patients. Research findings indicate that substance abusers with cognitive limitations, which may not comprehend the interventions, are more likely to drop out of treatment, relapse faster, and have poorer long-term outcomes in comparison to cognitively intact substance abusers.
Treatment Recommendations: An important first step in drug abuse treatment is to conduct a brief cognitive status examination that accurately identifies individuals with neuropsychological impairment. An early functional analysis of skills and resources that patients lack is a key component of behavioral addiction treatments. Furthermore, repeated neuropsychological evaluations during the treatment course may be important to inform the clinician as to when the patient's cognitive capabilities are improved so that the patient can understand more complex information.
After identifying core cognitive deficits, one treatment approach focuses on accelerating cognitive recovery of brain function. Although, it has been shown that cognitive performance appears to improve with extended abstinence, and that cognitive recovery may be related to better treatment outcome, the return to normal levels of recovery often extend beyond standard length of treatment. Thus, it may be important to accelerate cognitive recovery, since a great deal of learning is required early in treatment. A cognitive rehabilitation approach includes methods designed to enhance cognitive processing and teach compensatory techniques. Patients are typically assigned tasks designed to improve the identified deficits. Remediation sessions usually involve memory training and the development of problem-solving strategies. Environmental interventions may also be used to help compensate for information processing weaknesses. For instance, unambiguous cues may be used to prompt or discourage specific behaviors to help persons with memory impairment. The clinical significance is not yet clear regarding cognitive rehabilitation to enhance treatment response.
Another approach to treating drug abusers with cognitive limitations is to modify an existing treatment. In this approach, it is important to identify the core cognitive demands of the treatment, as well as the deficits/abilities of the patient, and to tailor the treatment to meet patient's abilities. Recommended adaptations include: decreased session length; increased session frequency; repeated presentation of therapeutic material; use of multi-modal presentation of material (visual, verbal, experiential); use of memory aids, such as appointment books, calendars, and mnemonics; provision of stress management to improve attention and concentration; use of simple language; assessment of retention with immediate feedback to clarify misunderstandings; and assignment of homework practice exercises. Other strategies include increasing the length of the treatment period so that more difficult and abstract concepts are presented later in treatment when cognitive processing has improved and to present information with less demanding content early in treatment.
Treatment Challenges: Many challenges exist in accommodating cognitively impaired drug abusers in treatment. First, there is a lack of knowledge about which clients should be targeted for rehabilitation or modified treatment. The onset of cognitive deficits is slow and insidious which contributes to the failure to detect serious impairment. Also, even though 30%-80% of substance abusers show mild to severe impairment, and there is a neurocognitive basis for "denial" inattention, distractibility and lack of motivation, neuropsychological testing is seldom conducted. Furthermore, other problem areas, like psychiatric comorbidities, tend to be focused on first because they are easier to diagnose. Neuropsychological assessment provides information that is useful to clinical decision-making; however, time constraints and declining resources generally preclude the use of assessment. The development of a sensitive brief screening measure would aid in identification of individuals with deficits. Another option would be to narrow the field of those who should be assessed by establishing profiles of high-risk patients. Secondly, there is a lack of knowledge about what is considered impairment and what is not. Definitions are needed regarding the qualitative and quantitative features of impairment. Finally and importantly, it has yet to be determined how best to treat cognitively impaired drug abusers once they are identified . Research findings related to the contribution of cognitive variables in the treatment outcome of drug abuse patients are variable. It is unclear if cognitive rehabilitation accelerates the rate of cognitive recovery, and if so, if it impacts treatment response and outcome? Treatment approaches tailored to the needs of the impaired drug abuser have not yet been developed or tested.
Suggestions for Future Research: There may be multiple pathways to achieving good treatment outcomes for cognitively impaired adults and adolescents. However, it is currently not known if treatment should be directed at accelerating recovery through cognitive remediation, modifying treatments to meet the cognitive abilities of the patients, or a combination of both. Research aimed at improving drug abuse treatment and HIV risk reduction interventions for individuals with cognitive deficits is critically needed. Specific recommendations to facilitate treatment for cognitively impaired drug abusers include research aimed at:
- testing a cognitive rehabilitation approach to enhance treatment outcome.
- developing and testing a modified treatment to match the abilities of impaired patients.
- developing a "cognitively friendly" treatment for drug abuse patients to be offered broadly with the flexibility for quick advancement. This "levels" approach to treatment would be useful in bypassing the problems associated with neuropsychological testing in treatment settings.
- examining the predictive validity of neuropsychological variables in the treatment of substance use disorders.
- developing a brief screening measure with sensitivity to aid in identification of cognitive deficits.
- testing if and how treatments for cognitively impaired drug abusers can be transported to the community, including how to train treatment providers.
- examining mediation and moderation relationships between impairment and intrapersonal capabilities such as psychopathology and medical status, change processes such as self-efficacy and motivation, and environmental factors such as social support.
- improving coping skills strategies for adolescents with poor neurocognitive abilities.
- establishing profiles of high-risk patients.
- dismantling key components of effective interventions.