A rudimentary knowledge of the different substances and their unique psychoactive effect is necessary in order to understand and treat substance use disorders because treating alcohol abuse is different from treating someone who has been abusing LSD or methamphetamines. In order to be effective, treatment must not only the physiological effects of the substance, but most also extend to the subjective psychological experience of the drug, the culture around the drug, the social views on the drug, the normal course of withdrawal, and finally, separation from use of the drug.
Underlying or co occurring emotional disorders must also be assessed since these disorders can mimic or exacerbate the effects of a mental disorder. Knowing the behavioral and mood altering effects of substances then is also essential for optimal assessment and treatment.
Substance abuse is not only a problem for the individual, but also leads to social and ethical problems for the society in which it occurs.
Finally, having an objective knowledge of drugs can help the treating professional understand when use of a substance is life threatening and should be referred for in patient and more intensive treatment.