Understanding “Other” (or Unknown) Substance-Related Disorders

“Other” (or unknown) substance-related disorders are a group of conditions listed in the Diagnostic and Statistical Manual of Mental Disorders, which serves as the main U.S. reference text for diagnosing mental illnesses. The manual includes these conditions in order to provide mental health practitioners with a way to diagnose significant substance-related problems that don’t fit the definitions for any individually recognized substance-related disorder.

Some of the “other” disorders contained in DSM 5, the 2013 edition of the Diagnostic and Statistical Manual, are the same as those listed in the manual’s previous edition. However, the DSM 5 also alters the definitions of some of the included disorders.

Substance-Related Disorder Basics

Substance-related disorders are mental disorders that stem in some way from the use of plants, drugs, or medications that significantly alter the normal, healthy function of the human brain and body. The DSM 5 lists forms of these conditions that include substance-related intoxication, substance-related withdrawal, “other” substance-induced disorders, and “unspecified” substance-related disorders. The DSM 5 also lists conditions called substance use disorders, which include problems once attributed separately to either substance abuse or substance dependence. The specific substances listed in the manual as causes of substance-related disorders are alcohol, cannabis (marijuana and hashish), hallucinogens, phencyclidine (PCP), inhalants, stimulant drugs and medications, opioid drugs and medications, sedative-hypnotic medications (tranquilizers), anxiolytics (anti-anxiety medications), tobacco and caffeine.

“Other” (or Unknown) Substance-Related Disorders

While the Diagnostic and Statistical Manual lists a range of substances known for their potential to trigger a substance-related disorder, it can’t possibly list every substance that could act as the underlying cause of a mental health issue. This is true, in part, because certain substances may only have negative psychological effects in limited numbers of the general population. It’s also true because licit and illicit drug and medication manufacturers frequently create new substances that only eventually make their way into official publications such as the Diagnostic and Statistical Manual. The “other” or (unknown) substance-related disorders exist so that doctors can describe and diagnose substance-related mental health problems that don’t appear in the manual by name. The DSM 5 includes five of these disorders: “other” (or unknown) substance use disorder, “other” (or unknown) substance intoxication, “other” (or unknown) substance withdrawal, “other” (or unknown) substance-induced disorder(s) and unspecified “other” (or unknown) substance-related disorder.

“Other” (or Unknown) Substance Use Disorder

The American Psychiatric Association, publisher of the Diagnostic and Statistical Manual, includes substance use disorder in the DSM 5 as part of a shift in scientific viewpoint regarding the nature of substance abuse and substance dependence. Whereas most doctors and researchers once believed that there is a logical, consistent way to tell the difference between abuse and dependence in any given individual, large numbers of experts now feel that the distinction between these two conditions is essentially arbitrary and scientifically inconsistent. In reflection of this change, people affected by a substance abuse- or substance dependence-related problem now receive a substance use disorder diagnosis, which takes both abuse and dependence into account simultaneously. When a use disorder occurs in connection with an unknown substance or a known substance not listed in the DSM 5, the “other” (or unknown) substance use disorder diagnosis applies.

“Other” (or Unknown) Substance Intoxication

Substance intoxication is a disruptive mental/physical state that arises either during active use of a given substance or during the period of time immediately following the use of a substance. Aspects of function commonly affected by intoxication include the ability to think clearly, the ability to control one’s body, the ability to control one’s behaviors, and the ability to control one’s emotions. “Other” (or unknown) substance intoxication is diagnosed when doctors don’t know what substance acts as the source of these disruptions, or when the substance in question does not appear in the Diagnostic and Statistical Manual.

“Other” (or Unknown) Substance Withdrawal

Substance withdrawal is a disruptive mental/physical state that arises when a habitual, heavy consumer or user of a substance suddenly discontinues substance use or sharply limits substance use. The specific symptoms of withdrawal, and the severity of those symptoms, vary according to the substance in question. In order to meet the standards for a mental health diagnosis, the symptoms present must produce a significant negative impact on the physical and mental wellbeing or everyday functionality of the affected individual. “Other” (or unknown) substance withdrawal is diagnosed when withdrawal stems from use of an unknown substance or a substance not specifically listed in the DSM.

“Other” (or Unknown) Substance-Induced Disorder

Substance-induced disorders are separately diagnosable mental disorders that appear as a result of substance use. The previous edition of the Diagnostic and Statistical Manual listed specific forms of these disorders, which include anxiety disorders, sleep disorders, mood disorders, amnestic disorders (amnesia) and psychotic disorders. Rather than taking this approach, DSM 5 includes one general listing, called “other” substance-induced disorders, which accounts for all of these conditions. Although it may seem a bit confusing, “other” (or unknown) substance-induced disorders are “other” substance-induced disorders that stem from the use of an unknown substance or a known substance not usually associated with substance-induced conditions.

Unspecified “Other” (or Unknown) Substance-Related Disorder

Sometimes, people negatively impacted by substance use don’t meet all of the requirements needed to diagnose a substance-related disorder. When this situation occurs in association with a known or listed substance, the DSM 5 accounts for it with an unspecified substance-related disorder diagnosis. An unspecified “other” (or unknown) substance-related disorder diagnosis applies when the source of a nonstandard substance-related issue is not known or does not specifically appear in the Diagnostic and Statistical Manual.