Anxiety Disorders and Substance Use Disorders: The Puzzle of Co-Occurrence

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Successful prevention and treatment of a variety of substance use disorders (SUDs) often demands unraveling a tricky knot: their co-occurrence with anxiety disorders (ADs). Many ADs first appear in youth, pre-adolescence, or early adolescence, before exposure to alcohol or drugs that lead to SUDs. Not all ADs, however, present themselves before SUDs. Specific ADs, such as generalized anxiety disorder or panic disorder, typically emerge after an individual develops a SUD. Recent studies into the interaction between SUDs and ADs show how each disorder can intensify the other, and recommend ways providers might calibrate intervention, screening, and treatment strategies to serve people diagnosed with co-occurring SUDs and ADs.

Rates of Co-Occurrence of AD and SUD

When ADs and SUDs co-occur, one common outcome is that the disorders negatively reinforce one another. In this scenario, each disorder makes the other worse. The presence of an AD may drive individuals to seek forms of self-medication – whether illicit or prescribed – that temporarily ameliorate uncomfortable symptoms. Over time, tolerance and dependence to alcohol, an illegal substance, or a prescription medication may develop. Once that happens, the path to misuse becomes more likely because withdrawal symptoms trigger continued and increased misuse.

A recent epidemiological study of 12-month and lifetime prevalence of SUDs among U.S. citizens reports that both have increased in the past 15 years. The measure of a 12-month prevalence of SUDs determines how many individuals presented the symptoms of a SUD in the 12 months prior to the study, which researchers conducted between 2012 and 2013. The lifetime prevalence measure, on the other hand, captures how many people have been diagnosed with a SUD in the course of their lifetime.

In this study, the 12-month prevalence of SUDs increased 100% over a decade (that’s double), while the lifetime prevalence increased by 50% over the same time period. In addition, lifetime prevalence of SUD correlates with several types of anxiety, including generalized anxiety disorder (GAD) and posttraumatic stress disorder (PTSD). Given this significant national increase in the prevalence of SUDs, researchers and clinicians around the country now have a compelling and exigent need to study the role co-occurring ADs play in the development of SUDs.

The Anatomy of Anxiety Disorders

A diagnosis of an AD means that an individual is experiences excessive fear and/or anxiety in relation to daily life. Both anxiety and fear are useful emotions, regulating successful interactions with the world by indicating danger and potential harm. Fear is typically about a present, specific object or event, whereas anxiety is triggered by a future, less specific event.

For example, a snake wriggling on a path may cause fear, which may cause an individual to take action to avoid the snake and a potential venomous attack.

Anxiety in advance of an impending meeting with a boss for a performance review might cause an individual to stay on top of their work tasks, and prepare more thoroughly for their review.

In both cases, the anxiety and fear are productive.

The subtypes of ADs identified as either preceding or trailing a SUD include social phobia, generalized anxiety disorder, panic disorder, and agoraphobia. Social phobia is most clearly likely to present before the onset of SUDs. Generalized anxiety disorder is more clearly likely to present after the onset of SUDs. Panic disorder and agoraphobia tend to be more likely to present before the onset of SUDS, but they can quite frequently present after the development of SUDs.

The earlier onset of social phobia, which is now called social anxiety disorder, may be explained by the fact that it typically emerges in childhood and early adolescence. Among the symptoms of social phobia/social anxiety disorder are:

  • Fear of interacting or talking with strangers
  • Fear that others are negatively evaluating your actions
  • Worry over embarrassing or humiliating yourself in social/public situations
  • Worry that others will notice your anxiety and its physical symptoms (sweating, shaky voice, trembling, etc.)

The symptoms of generalized anxiety disorder are also indicators of withdrawal from substances, explaining why this diagnosis is more likely to be made after an individual has a SUD. These physical symptoms include:

  • Difficulty sleeping
  • Muscle tension
  • Easily startled
  • Nausea, diarrhea, or irritable bowel syndrome

It’s easy to understand what an individual who experiences these symptoms on a daily basis may escalate their alcohol or drug use. The combination of withdrawal and preexisting anxiety combine to increase the subjective drive to self-medicate. This creates a negative, mutually reinforcing cycle: symptom, drug use, withdrawal, increased symptoms, increased drug use, increased withdrawal – it’s a pattern that’s difficult to break, and becomes increasingly difficult over time.

Insightful Intervention and Treatment

To help people stuck in these cycles of anxiety and drug use, the data indicates that clinicians working with individuals living with SUDs should include comprehensive screenings for ADs to best tailor custom treatment plans. For example, if a given SUD co-occurs with a panic disorder, the clinician may need to consider different pharmaceutical treatments in addressing both disorders. While the panic disorder may have preceded the SUD, earlier treatment of the panic disorder with the benzodiazepine class of medications, for example, may have accelerated the SUD. Of course, prescribing a benzodiazepine may still be indicated in the treatment of an individual who presents with a SUD and panic disorder. But nonetheless, thinking through these questions and alternative treatment options prove to be much better for treatment success.

Public health campaigns, on the other hand, aimed at preventing the development of SUDs among certain populations should consider the special features among these populations that make individuals prone to SUDs. For example, campaigns targeted at adolescents may benefit from bringing greater awareness to the likelihood of individuals diagnosed with social phobia/social anxiety disorder developing a SUD. Peer-pressure to conform to typical social interactions could lead adolescents to certain substances, such as alcohol, to dampen intense fear and anxiety in these settings. Likewise, awareness campaigns targeted at adults with social phobias can help them better resist peer pressure to have drinks at lunch and participate in happy hour in the evenings, which, in turn, can decrease their likelihood of developing a drinking problem, a substance use problem, or both.