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JAMA Psychiatry. 2015 Jun 1;72(6):593-602 |
This article (2) caught my eye in JAMA Psychiatry. Stimulant (methamphetamine, cocaine, prescription stimulants, and various synthetics) use disorders (previously called addictions) are difficult problems to treat. That is especially true because of the epidemic of adult Attention Deficit~Hyperactivity Disorder diagnoses and the cross contamination from the cognitive enhancement movement as well as new indications for stimulant prescriptions. Stimulant medications are widely available and generally work at some level for most people who take them leading to the common impression that: "I took my cousin's Adderall and it worked! Therefore I must have ADHD and need my own Adderall prescription." By the time that has happened it is usually very difficult for any physician to explain to this patient why a positive response to a stimulant does not equate to an ADHD diagnosis, especially if the prospective patient has been functioning at a high level and is presenting for diagnosis and treatment after doing extremely well in college and their first few years of professional school.
A second problem with the ADHD stimulant use issue is the misconception that people with "true" ADHD are less susceptible to the positive reinforcing effects of stimulants than people without ADHD. There are certainly subgroups of person with this diagnosis that do not like to take stimulants. They find that stimulants decrease their appetite, given them increased anxiety and insomnia, and in many cases leave them feeling more restricted, affectively blunted and less spontaneous. I find that these patients are generally selected out by the time they are adults. They had true ADHD diagnoses in middle school, did not like the stimulants, or in many cases their parents did not like the effect they were seeing and they were taken off of them. They may have developed significant coping strategies based on their dislike of stimulant effects. Like many adult psychiatric disorders there is no one uniform phenotype, and the phenotype of the person who was diagnosed either as a child or an adult and who gets a euphorigenic effect from stimulants and escalates the dose clearly exists and is seen in treatment centers. In many cases they have an iatrogenic diagnosis of bipolar disorder from a pattern of taking the month's prescription of stimulant in the first one or two weeks and then either going into withdrawal or using a depressant like alcohol, benzodiazepines, or opioids to treat the dysphoria and cravings associated with stimulant withdrawal.
There is also the situation where a person has been using high dose prescribed stimulants (taking more than prescribed) or using high doses of meth or cocaine off the street, where they develop a residual state that is identical to ADHD, but where the cause of the ADHD is the stimulant. I think it is an error to treat that residual state with stimulants. That residual state is generally associated with a profound level of impairment and lack of insight. The patient is aware of significant cognitive problems, attributes them to ADHD and often insists on treatment with stimulants despite a clear addiction to stimulants. They may insist that years or decades of stimulant use was their attempt to self diagnose and treat their own ADHD. It is very common for patients with substance abuse problems to give a history of no formal diagnosis in childhood, no school or occupational impairment, but to offer the opinion that they think they may have ADHD. All of these considerations lead to associated problems in providing care to people who have clear ADHD and stimulant use diagnoses.
That leads me to this multisite study (2) on the effects of high doses of extended release mixed amphetamine (ER MA) salts on both ADHD and cocaine use in patients who have both of these diagnoses. The doses used were 60 and 80 mg/day. The most commonly used current prescription versions of these drugs typically recommend a maximum dose in adults of 30 mg/day (1), but interestingly there is a "titrate to tolerability" statement in the package insert of a drug where 20 - 60 mg/day were used in trials with the statement "There was not adequate evidence that doses greater than 20 mg/day conferred additional benefit." The authors describe their dosing selections as "robust" and suggest that there is evidence that higher doses are needed to treat cocaine use problems.
Looking at authors methodology, their screening for this trial is instructive of the problems encountered in clinical practice. Of a total of 1614 patients screened, only 126 were ultimately randomized to placebo, 60 mg/day ER MA, or 80 mg/day ER MA. Five hundred and sixty two were screened out due to medical or psychiatric exclusion criteria. It is common in older populations of stimulant users to find significant cardiovascular morbidity in the form of cardiomyopathy, coronary artery disease, and arrhythmias and these were some of the exclusion criteria. The other aspect of this study that I really liked and would suggest implemented in everyday practice is the authors approach to blood pressure and heart rate specifically:
"Participants with blood pressure higher than 140/90 mm Hg or heart rate higher than 100 beats/min for 2 weeks or with single readings of blood pressure higher than 160/110mmHg or heart rate higher than 110 beats/min were discontinued from study medication."
It is always shocking to hear from a person who has been on stimulants for years that nobody has ever checked their blood pressure or pulse, especially when they are sitting in front of you and are hypertensive and tachycardic. This basic procedure should be done on any person taking stimulants, antipsychotics, antidepressant and for that matter any CNS active drug. If similar effects are noted with any of these medications they should be discontinued.
Another important aspect of this study is that although the patients were well screened, they were complex from a substance use standpoint with current alcohol (18.6 - 27.9%), cannabis (7 - 14%), and nicotine (45-65.1%) use disorders. The high levels of nicotine use are not surprising considering the epidemiological correlations between smoking and cocaine use and recent evidence about the epigenetic effects of nicotine in substance use disorders. The authors do not comment on whether there were different outcomes for the non-smokers in this study.
On the primary outcome measure for ADHD - a 30% reduction in the AISRS (Adult ADHD Investigator Symptom Rating Scale) 58.1% of the high strength group and 75% of the low strength group achieved that outcomes with odds ratios of 2.27 and 5.23 respectively (see text for confidence intervals). In terms of cocaine use outcomes the 80 mg dose resulted in fewer cocaine positive weeks (by any positive toxicology or report) and abstinence in the last three weeks. The numbers are given in the table below:
In my experience, a substantial number of patients with ADHD and either cocaine or amphetamine use disorder reach the end of the prescribing algorithm where they have failed or relapsed. In many cases that failure does not lead to a prescription being stopped for many reasons, a lack of information to the prescribing physician being foremost among them. In the real world there is no clinic that will follow patients three times a week with toxicology screens at most of those visits and offer them all cognitive behavioral therapy. Models currently funded by managed care companies and governments consist of patients being seen every one to three months for 20 or 30 minutes. Many of those visits are done by clinicians with little to no addiction experience. Within the medication maintenance literature, particularly with buprenorphine maintenance there are studies that suggest psychotherapy adds nothing to the outcomes. But even without that data what business manager would consider those therapists "cost effective" beyond the stimulant prescription?
A key element that I never see in these studies is the patient's subjective response to the stimulant at increasing doses. I have found that Koob's definition of addiction is generally predictive:
"Addiction is a chronic relapsing syndrome that moves from an impulse control disorder involving positive reinforcement to a compulsive disorder involving negative reinforcement."
A euphorigenic, hypomanic effect is usually the high risk positive reinforcer regardless of the substance taken. One of the theories of abuse deterrent approaches is that the pharmacokinetics of the substance used prevents rapid availability in the brain and this decreases abuse potential. Many abuse deterrent preparations fail because multiples of the dose can be taken and result in the positive reinforcing aspects of the addiction cycle. I consider the authors' paper to be elegant in its experimental approach. The graphic at the top of this page is first-rate as a source of information. It also illustrates the problem of coming up with a clinical trial that can be translated into practice. I would not consider implementing this strategy as a clinical approach until there was a long term study that looked thoroughly at all of the outcomes. At this time, I don't think the modest results of this short term study warrant the widespread practice of using extended release mixed amphetamine salts for cocaine use disorders. There are also legal issues with prescribing maintenance doses of controlled substances in order to "maintain an addiction" as some laws are currently written. I would have liked to see an attempt to characterize the subjective responses to methamphetamine use measured along with an analysis of whether the non-smokers did better than the smokers.
A key element that I never see in these studies is the patient's subjective response to the stimulant at increasing doses. I have found that Koob's definition of addiction is generally predictive:
"Addiction is a chronic relapsing syndrome that moves from an impulse control disorder involving positive reinforcement to a compulsive disorder involving negative reinforcement."
A euphorigenic, hypomanic effect is usually the high risk positive reinforcer regardless of the substance taken. One of the theories of abuse deterrent approaches is that the pharmacokinetics of the substance used prevents rapid availability in the brain and this decreases abuse potential. Many abuse deterrent preparations fail because multiples of the dose can be taken and result in the positive reinforcing aspects of the addiction cycle. I consider the authors' paper to be elegant in its experimental approach. The graphic at the top of this page is first-rate as a source of information. It also illustrates the problem of coming up with a clinical trial that can be translated into practice. I would not consider implementing this strategy as a clinical approach until there was a long term study that looked thoroughly at all of the outcomes. At this time, I don't think the modest results of this short term study warrant the widespread practice of using extended release mixed amphetamine salts for cocaine use disorders. There are also legal issues with prescribing maintenance doses of controlled substances in order to "maintain an addiction" as some laws are currently written. I would have liked to see an attempt to characterize the subjective responses to methamphetamine use measured along with an analysis of whether the non-smokers did better than the smokers.
George Dawson, MD, DFAPA
References:
1: Drug Facts and Comparisons. Wolters Kluwer Health. St. Louis, MO, 2013.
1. The figure at the top of this post is from reference 2 above and is used with permission from the American Medical Association, License Number 3660331303348. Copyright © 2015 American Medical Association. All rights reserved.
