Drug abuse and addiction is formally diagnosed as a Substance Use Disorder. The patient may either abuse the substance, or in more severe cases become dependent on the substance. Substance Abuse is defined as a problematic pattern of substance use resulting in significant impairment or distress, lasting at least 12 months, in which the patient has difficulty fulfilling obligations at work, school, or with family, using the substance in a situation where it could be physically hazardous, has legal problems as a result of substance use, or recurring problems in social situations and relationships. Substance Dependence is more severe and involves excessive use of the substance, inability to stop use of the substance, excessive time spent in using the substance, interference with social or work relationships, or continued use despite the worsening of physical or psychological symptoms. Patients with Substance Dependence can develop tolerance, which is the need for more of the substance to get the same effect, or withdrawal, in which a recognized set of symptoms come on with discontinuation of the substance.
Patients may develop Substance Abuse or Substance Dependence to a wide range of different substances such as:
• Amphetamines or methamphetamine
• Cannabis (marijuana)
• Hallucinogens such as LSD or mushrooms
• Inhalants such as paint or glue
• Opioids and opiates such as heroin or pills such as oxycodone
• Phencyclidine (PCP)
• Sedatives and antianxiety medications such as phenobarbital, benzodiazepines such as Xanax, or sleeping medications such as Ambien
Patients may develop a Substance Abuse or Substance Dependence to any addictive substance, or any combination of addictive substances. When the patient develops Substance Dependence to three or more substances at the same time, the patient is diagnosed with Polysubstance Dependence.
Substance abuse or dependence can causedepression, mania, anxiety, psychosis, and other psychological and psychiatric symptoms. These symptoms typically reduce over time if they are solely caused by the substance itself. Such substance-induced symptoms must be taken into account before making a separate diagnosis of another psychiatric disorder such as a Mood Disorder, an Anxiety Disorder, or a Psychotic Disorder. However patients with these diagnoses often abuse or become dependent on substances as a means of self-medication and thus may have both a psychiatric diagnosis and a Substance Use diagnosis (Dual Diagnosis patients).