The concept of anxiety has played an important role in the understanding of psychopathology and normal everyday behavior. Sigmund Freud believed that anxiety played an important role in the manifestation of psychopathology and in understanding psychological disorders. In Freud’s time, anxiety was differentiated from fear such that:

  • Anxiety was characterized as a inner state of uneasiness that was not triggered by any specific threat. It was a very vague and uncomfortable feeling.
  • Fear was characterized as a reaction to a concrete threat.

Over time, the two terms became synonymous, and anxiety is now considered a less intense feeling of fear. Today, anxiety is still broken down into state and trait anxiety:

  • State anxiety refers to a temporary feeling of jitteriness or uneasiness that is triggered by some type of threat. When the threat is removed, the anxiety resolves. Many people walking on a path in the woods and encountering a snake will experience anxiety. For most people, once the snake is gone, the anxiety dissipates.
  • Trait anxiety refers to how different people experience anxiety when they are exposed to the same type of threat. For instance, some individuals are extremely anxious around snakes, whereas others are not.

Everyone occasionally experiences anxiety related to a number of different conditions. The normal variation in anxiety that most people experience is not typically an issue that will lead to some sort of dysfunctional behavior or result in someone developing a substance use disorder. However, there are individuals who experience anxiety when faced with certain circumstances that is considered to be far in excess of what would normally be associated with the situation, or who experience anxiety chronically such that it does not dissipate.

Anxiety Disorders

axiety disorders
Is important to understand that normal anxiety is considered to be an evolutionary development that acts as a protective factor to help people acknowledge and/or avoid potential dangers. For example, an individual walking a path in the woods and seeing a snake who experiences anxiety is experiencing a reaction designed to protect the individual from a potentially harmful encounter. The experience of anxiety triggers the “fight-or-flight” mechanism (hopefully individuals seeing a snake in the woods will engage their flight mechanism). Moreover, one of the oldest laws in psychology known as the Yerkes-Dodson law states that at low levels of physical arousal (or anxiety) and extremely high levels of physical arousal (or anxiety), an individual’s performance on a specific task will deteriorate. Optimal performance occurs when physical arousal (or anxiety) is moderate.

Some individuals experience extreme high levels of anxiety that may be associated with specific situations, or that may appear to come out of nowhere, that lead to potential dysfunctional behavior. Some people will experience consistently high and dysfunctional levels of anxiety. When anxiety is the major component of a psychological disorder, an individual is diagnosed with an anxiety disorder.

A person with an anxiety disorder experiences anxiety that is out of proportion to the actual threat experienced (trait anxiety). In many cases, the anxiety does not dissipate when the potential threatening situation is resolved (state anxiety). This dysfunctional anxiety interferes with the person’s ability to function normally.

The American Psychiatric Association lists several different anxiety disorders, such as panic disorder, specific phobias, social anxiety disorder, and generalized anxiety disorder. In addition, there are other extenuating circumstances where anxiety may be dysfunctional. Individuals who have dysfunctional experiences with anxiety are also prone to develop substance use disorders.

Anxiety and Substance Use Disorders

anxiety and substance abuse
People who have dysfunctional experiences of anxiety, such as individuals with anxiety disorders, are at risk to also develop substance use disorders. A much cited study published in the Archives of General Psychiatry in 2004 revealed that nearly 18 percent of respondents who were diagnosed with a substance use disorder also met the diagnostic criteria for an anxiety disorder, and that the odds of having an anxiety disorder with a co-occurring substance use disorder were significantly higher than the odds of having an anxiety disorder alone. The findings that significant proportions of individuals diagnosed with substance use disorders also meet the diagnostic criteria for certain anxiety disorders, and that individuals diagnosed with anxiety disorders are likely to have substance use disorders, have been replicated in other studies. These findings indicate that there is a significant relationship between having dysfunctional levels of anxiety and the development of substance abuse.

Many individuals will wrongly assume that having one disorder causes one to develop the other, but this is not a valid assumption. In fact, there are three theoretical relationships between anxiety and substance abuse that explain the relationship between dysfunctional anxiety and the development of substance use disorders:

  • One explanation posits that if a person has a substance use disorder, this results in the person experiencing symptoms that also qualify them to be diagnosed with other certain types of psychological disorders. People who have developed physical dependence on alcohol will experience severe and dysfunctional anxiety during withdrawal periods. Severe physical dependence can trigger withdrawal symptoms only a few hours after people stop drinking. For these individuals, a substance use disorder would exist before being diagnosed with the anxiety disorder.
  • A hypothesis in lay circles proposes that individuals who already have certain types of psychological disorders, such as depression or anxiety, turn to substances like alcohol and drugs to self-medicate. These people are using the substance to attempt to control their anxiety. By definition, the anxiety disorder would have to appear before the substance use disorder.
  • A third and more likely explanation has been termed the shared liability model. In this explanation, it is hypothesized that individuals who are prone to developing psychological disorders have a number of risk factors. These risk factors can be inherent risk factors, such as certain genetic predispositions or neurobiological vulnerabilities. Risk factors can also be environmental in nature, such as experiencing extreme stress or trauma. Individuals who have these risk factors are prone to developing any number of different types of mental illness, including anxiety disorders and substance use disorders. If this model is valid, then either the substance use disorder or the anxiety disorder could appear first.

Research is indicated that the symptoms of the anxiety disorder often precede the development of a substance use disorder but this is not a consistent finding, and the research has not consistently pointed to a self-medication hypothesis. Because it is currently believed that the development of psychiatric or psychological disorders is a result of a number of interacting factors, it appears that the shared liability model has the most explanatory power. However, this is not to say that individuals do not self-medicate or that individuals with substance use disorders may not develop symptoms of anxiety disorders as a result of severe and chronic substance abuse. But it does appear that the notion of a shared liability model offers a more thorough explanation of the relationship between anxiety or any other psychological disorder and the development of substance abuse.

While any drug of abuse can be associated with a co-occurring anxiety disorder and substance use disorder, it is noted that alcohol, marijuana, tobacco, central nervous system depressant, and stimulant abuse appear to be prevalent in individuals with anxiety disorders.


anxiety treatment
Individuals with co-occurring disorders, the diagnosis of a psychological disorder such as an anxiety disorder and a co-occurring substance use disorder, require special considerations for treatment. Research has indicated that anyone diagnosed with co-occurring disorders needs to get treatment for both disorders at the same time in order for the treatment to be successful for either disorder. If an attempt is made to focus on treating one disorder and holding the others constant, this typically results in both disorders not responding to treatment.

Treatment programs for these individuals need to be as comprehensive as possible.

These individuals will typically require treatment that is delivered by a multidisciplinary team that includes psychiatrists, other physicians, psychologists and/or social workers, and other mental health workers. The treatment must be based on sound empirically validated principles (treatment principles that have been confirmed as being effective by research) and also allow for specific adjustments so care can be tailored to fit the specific case.

By delivering this comprehensive treatment package, the individual has a much better chance of a successful recovery from both the anxiety disorder and the substance use disorder.