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Novel Therapies for Cognitive Dysfunction Secondary to Substance Abuse: Page 4 of 4

Novel Therapies for Cognitive Dysfunction Secondary to Substance Abuse: Page 4 of 4

In cocaine use disorders, deficits in working memory, disinhibition, decision making, and emotional processing persist at mid-term recovery; at long-term recovery, there are persistent deficits in flexibility and decision making. Methamphetamine is one of the more cognitively pervasive drugs, since deficits in episodic and working memory, disinhibition, and emotional processing persist at long-term recovery.

In the case of heavy MDMA (3,4-methylenedioxymethamphetamine) use, deficits in episodic and working memory, selective attention, and disinhibition may persist at mid-term recovery, whereas only mild deficits in episodic and working memory are manifest at long-term recovery. In heroin addiction, deficits in memory, attention, initiation of controlled response, disinhibition, and emotional process-ing persist at mid-term abstinence, and at long-term abstinence, working memory and decision-making skills are still significantly altered. Finally, with alcohol dependence, there are deficits in memory, selective attention, and emotional processing at mid-term abstinence and persistent deficits in visual-spatial skills and decision making at long-term abstinence.

Research on rehabilitation of cognitive deficits in addiction is in its infancy, but it seems clear that deficits in working memory, disinhibition, decision making, and emotional processing are by far the most significant and the most pervasive, so those should be our targets. As in other applications of neuropsychological rehabilitation, there are 2 complementary routes we can follow: attempt to restore these processes through intense stimulation, and attempt to compensate these deficits to optimize performance during activities of daily living.

The results of a recent study that applied cognitive stimulation of working memory functions in psychostimulant-dependent patients showed significant reductions of disinhibition (defined as decreased preference for small immediate rewards over more delayed ones) after 1 month of training.23 We used a holistic approach that combines Goal Management Training (GMT) for rehabilitation of executive functions with mindfulness meditation for training of emotional feedback relevant to focused attention and decision making.24 Our results showed significant improvements in working memory, disinhibition, and decision making after 7 weeks of treatment for mixed alcohol and cocaine polysubstance dependence.25

GMT relies on cognitive stimulation and promotion of treatment-relevant activities of daily living; therefore, it may constitute a more thorough and easy way to generalize intervention. Both studies support the feasibility of applying cognitive rehabilitation in patients with substance dependence. Another option is to adjust usual cognitive-behavioral interventions to the individual profile of cognitive dysfunction of each patient. For example, these interventions may consist of feedback-based learning rather than complex instructions in patients with attention/working memory problems or of compensation of disinhibition problems with community reinforcement approach strategies based on the achievement of delayed rewards. Clearly, future research is needed to support the long-term effectiveness of these interventions on clinical outcome variables (eg, craving, relapse); in the meantime, we have reasons to support the usefulness of a neuropsychological approach to problems of substance dependence.

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References

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