Wednesday, January 10, 2007

One Drug For Another...

A recent study (Tiihonene et al., Am J Psychiatry 2007) compared aripiprazole (Abilify), methylphenidate (Ritalin) and placebo in the treatment of amphetamine addiction.

Here are the study results (quoting from the abstract):

Patients allocated to aripiprazole had significantly more amphetamine-positive urine samples than patients in the placebo group (odds ratio=3.77, 95% CI=1.55-9.18), whereas patients who received methylphenidate had significantly fewer amphetamine-positive urine samples than patients who had received placebo (odds ratio=0.46, 95% CI=0.26-0.81).

My problem with the abstract: The abstract concludes with a positive statement about methylphenidate, but says nothing about the drastic ineffectiveness of aripiprazole. I’ve not read the article, so I cannot say anything about what its actual text. I can say, however, that when a drug is related to drastically worse outcomes than placebo, as was the case for Abilify, then I think a statement should be put into the abstract’s conclusion about this finding. This is related to one of psychiatry’s big problems – focus on the positive (sometimes in a distorted manner), and ignore the negative. I’ll have to get the full text and look further.

Abilify’s performance: Why would people taking Abilify be so much more likely to use amphetamines compared to people taking placebo? Well, if I’m big into amphetamines and somebody puts me on a drug that includes sedation, akasthisia (extreme agitation), tremor, restlessness, and potential extrapyramidal symptoms (movement disorder) as side effects, I can see how someone who likes amphetamines might be tempted to jump back into the amphetamine habit.

Methylphenidate’s performance: Using a minor stimulant such as Ritalin makes some sense in that you’re following the same logic as replacing heroin with methadone. Replace a more dangerous habit with a less dangerous one. Ritalin might help some folks get the stimulant effect they’re looking for without the dangers of (meth)amphetamine use. However, there’s no free ride – there are likely some issues with long-term use of methylphenidate as well, though I’d rather be a regular Ritalin user than a so-called “Meth Head.”

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