Substance Use Disorders
"Substance use disorders" refers to a spectrum of aberrant behaviors related to use of psychoactive substances, which can alter normal brain activity and have wide ranging consequences for a person's health and well being. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM 5) lists 11 criteria for alcohol and other substance use disorders (1) These criteria primarily relate to whether the patient has experienced consequences as a result of loss of control over substance use. Notably, the emphasis on severity in the new DSM 5 nomenclature has replaced the DSM IV's focus on the distinction between "substance abuse" and "substance dependence" The DSM V's emphasis on severity removes some of the confusion between the term "substance dependence" and physical dependence, a state in which the body has adapted to long term use of a substance and experiences withdrawal in its absence. While most patients with severe substance use disorders are physically dependent, this dependence alone is not sufficient for the diagnosis. The term "addiction" remains in widespread use and refers to the long term, neurobiological disease that overlaps with moderate or severe substance use disorders as defined in the DSM 5 (2) Epidemiology How common are substance use disorders? Alcohol use and other substance use disorders, excluding tobacco, contribute to more than 90 000 deaths in the United States annually (3) Despite such dire consequences, these conditions are often inadequately addressed in outpatient care. And yet, substance use disorders have much in common with other medical conditions that are commonly treated in primary care and other medical settings: genetic, environmental and behavioral roots; enduring biological changes that lead to a chronic, relapsing and remitting course; and response to both medical and behavioral treatment (4) Alcohol use disorders remain the most common substance use disorder in the United States. Nearly 30% of Americans 18 years of age or older exceed recommended limits for alcohol consumption and can be considered "at risk" or "risky" drinkers (5) Fewer, but still a substantial minority, have consumption patterns indicative of an alcohol use disorder (AUD) The 12 month and lifetime prevalences of AUD among adults in the United States are 14% and 29% respectively (6) Approximately 22.3 million Americans aged 12 years or older were current users of illicit drugs in 2013, representing 9.4% of that population. According to the 2013 National Survey on Drug Use and Health, marijuana was by far the most commonly used drug (7.5% followed in descending order by prescription drugs (2.5% most of which are opioids) cocaine (0.6% hallucinogens (0.5% inhalants (0.2% and heroin (0.1% (7) Of note, prescription opioid use disorders in the United States are increasing and seem to be a gateway to heroin use, which is both cheaper and more abundant in some parts of the country. One consequence is an epidemic of opioid overdoses, with those involving prescription opioids increasing 3 fold, and heroin overdoses increasing 5 fold from 2001 to 2013 (8) Methamphetamine "crystal meth" use of which has declined slightly, is uncommon on a population level but remains a major problem in some regions of the country. In addition, concern about designer drug use young adults is increasing; these drugs include synthetic cannabinoids (also known as K2 or "spice" which were used more commonly than any drug except cannabis among high school seniors in 2013, and substituted cathiones including mephredone or "bath salts" (9) What are the risk factors? Studies suggest that genetic polymorphisms may contribute to as much as 40% to 60% of an individual's risk for addiction (10, 11) Environmental factors in childhood or adolescence may also be particularly important, including age of first exposure to alcohol or drugs (12) and adverse childhood experiences (13) Finally, substance use disorders are commonly associated with psychiatric comorbidities, including depression, anxiety, and bipolar disorder. These conditions may contribute to an individual's vulnerability to addiction; in addition, anxiety and depressive symptoms may be a consequence of long term substance use. Prevention What personal, community, and health system measures are effective in preventing substance use disorders? Parents who model abstinence or modest alcohol consumption are a positive influence on their children (12) Parents and children should be aware that early use of drugs or alcohol is a risk factor for later development of a substance use disorder. Policy measures that have been effective in reducing underage drinking and other adverse drinking related outcomes at all ages include price regulations (e.g. alcohol taxation and minimum pricing) and measures to reduce alcohol availability (e.g. age limits for purchase, restricting hours and days of sales, and marketing restrictions) (12, 14) Examples of community and policy measures being considered or implemented to reduce prescription drug abuse include initiatives to dispose of remaining controlled substance prescriptions, physician safe opioid prescribing education, restrictions on such pain clinic practices as directly dispensing opioid analgesics, and limitations on the quantity given in a first opioid prescription. As yet, evidence is limited about the effectiveness of these strategies, but in Florida, implementation of a prescription monitoring program in combination with pain clinic restrictions reduced the amount of total opioids prescribed and was associated with a decline in overdose deaths (15) What health system measures are effective in reducing or preventing unhealthy substance use? The Screening, Brief intervention and Referral to Treatment (SBIRT) is an important tool for physicians and primary care teams to reduce alcohol use. Safe practices for opioid prescribing for chronic pain, including the use of prescription monitoring programs, are increasingly being implemented as a strategy aimed at reducing the burden of prescription opioid use disorders and/or overdose. Unhealthy alcohol use is consumption at a level that has been determined in epidemiologic studies to have negative health consequences.(16) Unhealthy alcohol use encompasses a spectrum from "risky" use to an alcohol use disorder (Figure) As defined in the United States, for men aged 65 years and younger, risky use means more than 4 drinks per occasion or more than 14 drinks per week; for men older than 65 years and women, risky use is more than 3 drinks per occasion or more than 7 drinks per week (5, 16) Unhealthy alcohol use goes beyond risky use to become a disorder when a person experiences negative consequences and/or loss of control around their drinking, as defined in the DSM 5. For patients who have risky use, brief interventions in primary care can reduce the amount of alcohol consumed. Figure. Unhealthy substance use. A systematic review of 12 studies found that in the subset of studies involving good quality, brief, multicontact behavioral counseling interventions participants reduced the average number of drinks per week by 13%34% more than controls, and the proportion of participants drinking at moderate or safe levels was 10%19% more than controls. Such multicontact interventions were more effective than single contact interventions (16) Of note, patients with risky use who do not have an alcohol use disorder benefit the most from screening and brief intervention; SBIRT benefits have not been demonstrated for persons with an alcohol use disorder, who should receive more extensive treatment (17) SBIRT for alcohol is a U.S. Preventive Services Task Force (USPSTF) grade B recommendation, meaning there is high certainty that the net benefit is moderate, or there is moderate certainty that the net benefit is moderate to substantial. In a primary care practice, SBIRT initially involves screening for unhealthy alcohol use using a validated tool (see Diagnosis) Patients who screen positive should have further assessment for an alcohol use disorder, and physicians or practice staff should conduct a brief investigation. This investigation is a conversation in which the provider uses motivational interviewing techniques to give feedback about the patient's level of alcohol use, offers advice, and elicits goals and next steps from the patient. If there is concern for an alcohol use disorder, the patient should be referred for further treatment. All patients with a positive screen should receive planned follow up. In contrast, brief interventions for drug use have not been shown to be effective. The ASPIRE study randomly assigned 528 primary care patients with drug use to 1 of 2 brief counseling interventions or to no intervention. It found that no strategy decreased drug use at 6 months, regardless of the type of drug or severity of use (18) A second study of 868 patients with drug use randomly assigned to a single brief intervention with an attempted follow up telephone booster, compared with a handout alone (control group) found that the brief intervention had no significant effect on drug use or addiction severity at 3, 6, 9, or 12 months (19) Nonetheless, physicians should consider asking about drug use when observing deteriorating social functioning, finding a family history of substance use disorders, or diagnosing comorbidities often associated with substance use (e.g. hepatitis C, upper extremity abscess) Clinical cues, such as pancreatitis or unexplained elevated liver function test results, should also trigger investigation about alcohol use. How can opioids for chronic pain be prescribed safely and effectively? Physicians' prescribing practices over the past 2 decades have contributed to increasing rates of opioid use disorder and overdose in the United States. Clinical experience provides insight into which patients being considered for opioid me
Annals of Internal Medicine