Substance use disorder: Clinical sciences

Substance use disorder is a medical condition characterized by the inability to control the consumption of a substance despite adverse health and social consequences. The cause of substance use disorder is multifactorial and includes psychological, biological, social, and environmental factors. Based on criteria defined in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, or DSM-5, you can categorize a substance use disorder as mild, moderate, or severe.

Okay, if a patient presents with a chief concern suggesting a substance use disorder, first perform an ABCDE assessment to determine if the patient is unstable or stable. If your patient is unstable, stabilize the airway, breathing, and circulation, which might require endotracheal intubation with mechanical ventilation. Next, obtain IV access and put your patient on continuous vital sign monitoring, including blood pressure, heart rate, pulse oximetry, and cardiac telemetry.

Here’s a clinical pearl to keep in mind! Patients with substance use disorder might present with a few potentially unstable conditions. For example, cocaine toxicity can cause cardiac ischemia and seizures, whereas heroin or other opioid toxicity can result in severe drowsiness, respiratory depression, and coma. Benzodiazepine toxicity can also cause CNS depression, whereas benzodiazepine or alcohol withdrawal can cause potentially fatal seizures!

Now that we’ve addressed unstable patients, let’s return to the ABCDE assessment and take a look at stable patients. If the patient is stable, first obtain a focused history and physical exam. Next, assess for substance use with a screening test, such as the Drug Abuse Screening Test, or DAST-10. DAST-10 contains ten “yes” and “no” questions about substance use over the past 12 months and includes illicit drugs, prescription medication and over-the-counter medication. However, keep in mind that this screening test excludes alcohol use.

Now, here’s a high-yield fact! If you suspect your patient is using more than one substance, you might want to use the ASSIST questionnaire, which stands for Alcohol, Smoking, and Substance Involvement Screening Test. This is an 8-question test that identifies misused substances, such as tobacco, alcohol, cannabis, cocaine, stimulants, inhalants, sedatives, hallucinogens, and opioids.

Next, your patient or their close contact may report concerns about their substance use, but keep in mind that some patients may conceal or minimize concerns related to substance use despite associated relationship struggles, such as strained friendships or difficulties with co-workers.

Sometimes, there might be a history of a mood or personality disorder, such as depression or borderline personality disorder, or a childhood trauma, such as parental abandonment. Family history may reveal alcohol or other substance use disorders. Physical examination may reveal abnormal blood pressure, needle puncture marks on the skin, and damaged nasal septum.

Additionally, you may observe abnormal pupils, which could be either dilated or constricted depending on which substance is involved. But, in some cases, your patient’s examination might be completely normal. Finally, if the DAST-10 score is 3 or higher, you should suspect a substance use disorder!

Here’s a clinical pearl! Different substances cause different signs and symptoms. For example, acute toxicity from stimulants like amphetamine and cocaine cause hypertension, tachycardia, and dilated pupils. On the other hand, CNS depressants, such as barbiturates and benzodiazepines, cause somnolence, slowed respiratory rate, hypotension, and pinpoint pupils. Next, with cannabis use, look for conjunctival injection; while those using phencyclidine might present with nystagmus.

Okay, once you suspect a substance use disorder, assess the DSM-5 criteria for substance use disorder. The DSM-5 lists eleven criteria that fall into four general categories including impaired control, physical dependence, social problems, and risky use.

First, let’s discuss factors suggesting impaired control, like if your patient is consuming more substances than intended or for a longer duration than intended. Next, they might be spending more time obtaining, consuming, or recovering from substances; or they continue to use substances despite insight into the problem, like after legal consequences.

Next up is physical dependence, like if they report cravings for substances; have unsuccessful attempts to decrease or stop using them; or even develop withdrawal symptoms, such as tremor or restlessness. Additionally, over time, your patient could develop tolerance to a specific substance, which means they have to take more of it to reach the desired effect.