[pdurrant]

Originally Posted by Cinisajoy

According to the DSM-IV, yes that is one of the criteria.

I'm addicted to pedantry.

Appendix C DSM-IV Criteria for Substance Dependence

"A maladaptive pattern of substance use, leading to clinically significant impairment or distress, as manifested by three (or more) of the following, occurring at any time in the same 12‐month period (emphasis ours):

1. Tolerance, as defined by either of the following:
   • A need for markedly increased amounts of the substance to achieve intoxication or desired effect
     or
   • Markedly diminished effect with continued use of the same amount of the substance
2. Withdrawal, as manifested by either of the following:
   • The characteristic withdrawal syndrome for the substance
     or
   • The same (or a closely related) substance is taken to relieve or avoid withdrawal symptoms
3. The substance is often taken in larger amounts or over a longer period than was intended
4. There is a persistent desire or unsuccessful efforts to cut down or control substance use
5. A great deal of time is spent on activities necessary to obtain the substance (e.g., visiting multiple doctors or driving long distances), use the substance (e.g., chain‐smoking), or recover from its effects
6. Important social, occupational, or recreational activities are given up or reduced because of substance use
7. The substance use is continued despite knowledge of having a persistent physical or psychological problem that is likely to have been caused or exacerbated by the substance (e.g., current cocaine use despite recognition of cocaine‐induced depression, or continued drinking despite recognition that an ulcer was made worse by alcohol consumption)

"

I don't see anything about the substance being illegal or hard to obtain.