If you’ve used foul-tasting nail polish to prevent yourself from biting your nails, you’ve experienced aversion therapy on a minor scale.

Aversion therapy, also called aversive therapy or aversive conditioning, is a controversial type of treatment.

Aversion therapy aims to help you end unwanted or harmful behaviors by associating the habits with a negative or unpleasant stimulus.

This therapy has been used for various challenges, including substance use disorders, smoking cessation, and even nail-biting.

Most controversially, aversion therapy is called conversion therapy when used to “treat” sexual orientation. But sexual orientation isn’t a condition, and it doesn’t need treatment. Aversion therapy used as conversion therapy has been deemed ineffective, harmful, and unethical.

Aversion therapy conditions you to associate a behavior with an unpleasant sensation. The therapy is meant to discourage you from engaging in an unwanted habit. In other words, aversion therapy creates deterrents to some of those behaviors you’re motivated to give up.

The approach is based on classical conditioning — you respond to stimuli based on repeated experiences with them.

The most well-known example of classical conditioning is Pavlov’s experiment with dogs.

In sum, the experiment had a bell ring before dogs were fed. After repeating this several times, dogs began to salivate in response to the sound of the bell alone, regardless of whether they saw or smelled food.

Aversion therapy is similar, but the stimulus is unpleasant.

For example, under the supervision of a therapist, someone might receive an electrical shock while being shown a picture of a cigarette.

Over time, they’ll associate the thought of smoking with the sensation of the electrical shock, causing them to reject cigarettes.

Another common example of aversion conditioning is using nail polish to prevent nail-biting.

People commonly paint their nails with clear polish or aloe, which tastes unpleasant. Over time, they begin to associate nail-biting with this unpleasant taste and stop wanting to bite their nails.

Aversion therapy commonly involves the following stimuli:

  • nausea-inducing drugs (emetics)
  • electrical shock
  • unpleasant imagery
  • nauseating smells and tastes
  • unpleasant tastes
  • physical pain
  • shame

Although aversion therapy is used to reduce various unwanted behaviors, most aversion therapy research is for alcohol use disorder.

Research from 2017 looked at the effectiveness of aversion therapy for alcohol use disorder. In particular, the study looked at chemical aversion therapy.

In chemical aversion, also called emetic therapy, you’re given emetics (medication that causes nausea or vomiting). You’re then given alcohol so that you feel ill.

After some repetition, you’ll begin to associate alcohol use with nausea and vomiting.

In the study mentioned above, participants reported avoiding alcohol 30 and 90 days after treatment, and 69% of participants reported sobriety a year later.

However, there has been no follow-up after a year, which means there’s no clarity about the long-term effects of the therapy.

Aversion therapy isn’t considered a first-line treatment for alcohol use disorder or any substance use disorder.

Effective treatments for substance use disorder might include talk therapy, support groups, or medication. Many people benefit from in-patient treatment.

Many studies, such as this 1993 study on using aversion therapy to treat dependence on cocaine, alcohol, and marijuana, noted that the effectiveness of the therapy depends on a variety of other factors.

These factors included the participants’ stress levels, social environments, and whether they attended support groups.

A pilot study from 1990 looked at 20 people treated for cocaine dependence. Researchers used a cocaine substitute to evoke the sight, smell, and taste of cocaine in patients on nausea-inducing drugs.

A lot of this research is quite dated. There’s very little recent research on aversion therapy.

Because aversion therapy involves the use of unpleasant stimuli, it’s quite controversial.

Some therapists think it’s unethical because it uses punishment as a therapeutic tool. Any punishment may lead to feelings of shame and guilt, which in turn may impact your mental health.

Ineffectiveness of aversion therapy

The research on the effectiveness of aversion therapy is mixed.

Overall, research on aversion therapy for alcohol use disorder suggests that it can be effective in the short term. Still, there are few rigorous studies on the long-term effectiveness of aversion therapy.

There are also concerns that many people relapse after the therapy has ended.

One of the most comprehensive studies on the long-term effects of aversion therapy dates to the 1950s.

The research showed that many participants didn’t stop alcohol use in the long term. After 1 year, 60% of participants had abstained from alcohol. This number dropped to 51% after 2 years, 38% after 5 years, and 23% after 10 years.

There’s a lack of research that supports the use of aversion therapy for other conditions.

Aversion therapy and conversion therapy

Perhaps most controversy surrounding aversion therapy has to do with its association with conversion therapy, which is an attempt to “treat” homosexuality or bisexuality.

Sexual orientation isn’t a health condition, though.

Although, up until 1973, homosexuality was included as a mental illness in the Diagnostic and Statistical Manual of Mental Disorders (DSM). Aversion therapy was seen as a way to “cure” homosexuality.

But sexual orientation, gender identity, and gender expression aren’t health conditions. There’s no need for a cure or treatment.

Inevitably, evidence has repeatedly shown that conversion therapy is both ineffective and harmful, often resulting in significant psychological harm.

Using aversion therapy to “change” sexual orientation is now considered unethical. It’s a violation of the ethical codes of the American Psychological Association, the American Psychiatric Association, and numerous other professional bodies.

You can often change minor habits on your own. There are many helpful techniques for changing a habit, including:

  • removing cues
  • changing your environment
  • replacing the habit with something else

But if you find it hard to change that habit, or if you have a more complex challenge such as a compulsion or substance use disorder, it might be helpful to seek professional support.

Behavioral therapies, such as cognitive behavioral therapy (CBT), can be helpful for substance use disorders and to address other unwanted behaviors. Family and marital counseling might also be beneficial.

Similarly, if you want to stop a habit that relates to another underlying issue, a support group and psychotherapy could be helpful. For example, if you bite your nails out of anxiety.

Aversion therapy is a controversial treatment, and there’s a lack of rigorous research on its long-term effectiveness. Because of this, it isn’t considered a first-line treatment for alcohol use disorder, substance use disorder, or other mental health challenges.