The clinical presentation can somewhat vary depending on the drug used, but the persistent need for drug use despite potentially harmful consequences, inability to regulate the frequency of its consumption and prioritizing its consumption over all other activities are hallmarks of drug dependence [1]. Two main types of dependence are recognized [2] [3]:

• Physical - Avoidance of undesired physical effects that occur due to the cessation of drug use, or withdrawal, are the primary reason for continuing drug use and development of dependence. Central nervous system hyperactivity, mydriasis, tremors, gastrointestinal irritation, and diarrhea are typical for opioid withdrawal, including heroin, while tachycardia, hyperreflexia, confusion, and seizures are reported after cessation of benzodiazepine use. Physical dependence is typical for cocaine, (presenting as a serious depressive reaction and intense fatigue accompanied by sleepiness) and alcohol, which usually manifests with CNS hyperactivity and constitutional symptoms, although more severe signs (hallucinations, delirium tremens) may be seen in severely dependent individuals.
• Psychological dependence - Euphoria, alleviation of anxiety, alterations in behavior, perception, and mental state, are the main features of dependence on hallucinogenic substances (lysergic acid, mescaline, psilocybin), marijuana, amphetamines and 3,4 -methylenedioxymethamphetamine (MDMA).

It is important to note that both physical and psychological dependence may be encountered in patients, making additional criteria highly useful in defining the diagnosis. Symptoms such as craving, tolerance (necessity to use larger amounts over time), repeated attempts to quit or control drug use, as well as giving up daily life activities due to dependence can be reported. When three or more symptoms are reported within a 12-month period, the diagnosis can be confirmed based on clinical criteria [2] [4].

The diagnostic workup must start with a carefully obtained patient history, as only a few questions during the interview may reveal the cause of symptoms and the substance that caused dependence. Physicians must bear in mind that peak dependence rates are during adolescence - Alcohol and marijuana dependence most likely occurs around 17-18 years of age, whereas cocaine abuse peaks around 23-25 years. of age [5]. What is worrisome is that more than 10% of cocaine, marijuana and alcohol users become dependent within the first 10 years of use [5]. These findings further emphasize the importance of a meticulous patient history regarding prior substance use and additional questions that will identify whether diagnostic criteria for dependence can be met [2]. More importantly, information from parents, close relatives or friends may be particularly helpful when there is a suspicion of drug dependence, as the patient may not always disclose such information. If the diagnosis is not confirmed, toxicology testing can be performed for marijuana, cocaine, opioids, amphetamines, phencyclidine, benzodiazepines, barbiturates, and alcohol [2]. Urine is tested most commonly, while blood, saliva, sweat or hair samples can be used as well [2].

1. Gould TJ. Addiction and Cognition. Addict Sci Clin Pract. 2010;5(2):4-14.
2. American Psychiatric Association. Diagnostic and statistical manual of mental disorders. Fifth Edition. Arlington, VA: American Psychiatric Publishing; 2013.
3. Porter RS, Kaplan JL. Merck Manual of Diagnosis and Therapy. 19th Edition. Merck Sharp & Dohme Corp. Whitehouse Station, N.J; 2011.
4. Hasin DS, O’Brien CP, Auriacombe M, et al. DSM-5 Criteria for Substance Use Disorders: Recommendations and Rationale. Am J Psychiatry. 2013;170(8):834-851.
5. Wagner FA, Anthony JC. From first drug use to drug dependence; developmental periods of risk for dependence upon marijuana, cocaine, and alcohol. Neuropsychopharmacology. 2002;26(4):479-488.