What are the differences between ibogaine and psilocybin as treatments?

Psilocybin works primarily through one type of serotonin receptor in the brain. Ibogaine targets dozens of different receptor types and transport proteins simultaneously, with moderate to weak binding affinity. One specific receptor type involved in nicotine signaling appears to be central to ibogaine's anti-opioid effect. That breadth makes ibogaine pharmacologically more complex and harder to control.

The difference in safety is the most pronounced. Ibogaine prolongs the heart's electrical rhythm in a way that can lead to cardiac arrest; multiple deaths from this have been reported. In addition, the substance is also toxic to nerve cells at higher concentrations. Psilocybin shows no comparable cardiotoxicity or nerve damage in the available literature. This makes ibogaine considerably riskier to use, especially outside medically controlled settings.

Psilocybin has more and better-controlled clinical data. Multiple clinical studies show promise for alcohol and tobacco addiction, with reductions in craving and increases in sustained abstinence, most strongly in combination with psychotherapy. For opioid addiction, ibogaine does not yet have a single double-blind randomized study proving effectiveness. The positive signals come from uncontrolled or retrospective studies with a high risk of bias. Only for cocaine addiction does one small randomized study with a positive result exist, but that is far too little to draw conclusions from.

In animal research, ibogaine reduced the intake of opiates, cocaine, amphetamines, and nicotine -- a broad spectrum that psilocybin does not demonstrate. Whether this works the same way in humans has not yet been proven. A derivative compound (18-MC) retained the anti-craving effect in animal models without ibogaine's side effects, but clinical trials in humans were still planned at the time of publication.

Psilocybin does not itself cause addiction, which distinguishes it from most other substances considered for addiction treatment. This has been less thoroughly studied for ibogaine. Legally, both substances have restricted availability: ibogaine is entirely illegal in many countries, while psilocybin is in the early stages of regulatory recognition for therapeutic use in some countries.