Thursday, October 23, 2008

How Addictive is Ritalin?

ADHD Medications

The controversy and discussion surrounding the safety of medications for ADD and ADHD is nothing new. Among the most common criticisms of these drugs are concerns about their abuse potential and their potential risks of being habit-forming drugs. Methylphenidate (the generic name for Ritalin and Concerta), has often been mentioned in the same sentence as "cocaine", especially among the "anti-medication" and "alternative treatment" sites for ADHD treatment options. While some of these comparisons are definitely warranted, the chemical structures and modes of action of ADHD stimulants such as amphetamines and the amphetamine-like methylphenidate and the illegal street drug cocaine do bear some striking resemblances. However, it is important that we do not get lost in the hype surrounding these relationships, and instead immerse ourselves in only the facts.

In the field of organic chemistry, even minor alterations to a drug's molecular makeup can result in significant functional differences. With this in mind, however, investigation into the abuse potential of stimulant ADHD medications such as Ritalin, Concerta, Daytrana, Adderall, Dexedrine, and Focalin should be carried out in a thorough, unbiased manner. A review article from the Journal of Clinical Psychiatry on the abuse potential of the ADHD drug methylphenidate investigated key properties of the drug that play a major role in abuse potential (such as drug absorption, products produced when the drug is metabolized, and how fast the drug clears from the body). Some key findings of the article on this popular stimulant medication are summarized below:

  1. When injected, methylphenidate, cocaine, and d-amphetamine all produced similar reinforcing effects in human subjects (keep in mind that injections produce drug effects that occur much faster than those taken orally in almost all cases)
  2. Sleep deprivation boosted the reinforcing effects of methylphenidate.
  3. Methylphenidate displayed similar abuse potential to d-amphetamine for a number of studies of the general population (read "non-ADHD" population).
  4. PET scans of the brain following methylphenidate and cocaine (when both were injected) showed similar absorption rates and binding levels to their target (called the Dopamine Transporter Protein or DAT. For more more info on the DAT and ADHD, please click here). However, methylphenidate was cleared much more slowly than cocaine, which correlates to a significantly lower addiction potential for the popular ADHD drug. A quick note about this: The faster a drug is absorbed in the brain, the greater the "high" is, typically. Since injections and snorting both get the drug into the system faster than when taken orally, these methods typically lead to much greater highs and addiction potentials. Additionally, the faster this drug is then cleared, the more it is "missed" by the brain, which also results in a greater addiction potential. So for a fast-acting and fast-clearing drug, the addiction potential is typically very high. For comparison sake, methylphenidate takes about 10 minutes to enter the brain when injected (for cocaine, it is about 5 minutes), and then takes about 90 minutes to clear halfway (for cocaine it is around 20 minutes). Thus, due to its slower uptake and even slower clearance rate, methylphenidate runs a much lower risk of being habit-forming than cocaine.
  5. Oral administration of methylphenidate is much slower than this, often taking at least 1-2 hours to peak in concentration in the brain. Extended and slow-release versions of the drug (Concerta, Ritalin-SR) reduce the abuse potential even further.
  6. Individuals with ADHD are thought to have a higher amount of binding sites (DAT, see point #4) for these stimulant medications than do those without ADHD. According to the author, this makes individuals with ADHD less susceptible than the general population to habit-forming addictions surrounding the use of the stimulant methylphenidate. A more detailed explanation for this is given below:

Further explanation for Item #6 above: Although neuroscientists still disagree over the mechanism of action of both medicated and illegal stimulants, it is believed that when this DAT protein is "plugged up" or "blocked" by these stimulants, it cannot shuttle free amounts of the brain chemical dopamine into the surrounding cells. As a result, the levels of free dopamine between neuronal cells builds up. Since dopamine plays a key role in the "reward" process, it can also play a major role in both "highs" and "addictions" (both of which seek out these "rewards").

If individuals with ADHD have more of these transporter proteins to begin with, they are less likely to oversaturate all of these transporters. As a result, they are less susceptible to this dopamine buildup and the highs and addiction potentials that go along with it. In other words, individuals with ADHD can often accommodate higher levels of stimulant medications such as methylphenidate, making them less susceptible to addiction-level effects.

Based on this article and a number of other sources I have either read or followed, here is my overall take on the topic of addictions to ADHD stimulant medications:

I earnestly believe that when properly diagnosed, properly monitored by a competent physician or related professional, and by proper compliance by the medicated individual, ADHD medications are relatively safe, and the risk of developing an addiction a medication such as methylphenidate is relatively low.

Of course, as we've seen above, individuals who are not diagnosed with ADHD and take methylphenidate for recreational purposes, the potential habit-forming effects of the drug can at least approach the levels of cocaine or amphetamines. Keep in mind that the right medication at the wrong dosage can easily be just as (or even more) damaging than having the wrong medication.

Yes, stimulant drugs prescribed for ADHD are often closely related to cocaine in both chemical structure and mode of function, but the small differences between the two are sufficient enough to form a "safety barrier". Given the fact that so many undiagnosed individuals with ADHD or other related disorders often tend to "self-medicate", the dangers of "un-treatment" are just as real and just as hazardous. Keep in mind that "self-medication" is, by nature, a much more erratic form of treatment and typically abounds in negative side effects.

This is not to say that non-medication treatments should never be explored or considered as viable options for treating ADHD. Many of the so-called "alternative treatments for ADHD" are surprisingly well-grounded and increasingly-researched. However, I remain highly skeptical to those who claim that all cases of ADHD can be handled exclusively and completely by natural means. Natural remedies can be very effective for numerous cases involving ADHD, but their scope and range of applications are somewhat limited.

Please check back later for future posts related to many of these important topics on ADHD!