An adult might suck their thumb due to stress, anxiety, or age regression. The effects of this habit over time may include blisters or issues with the teeth.

Many children stop sucking their thumb at a young age. However, some people continue to suck their thumbs into adolescence or adulthood.

In this article, we will discuss the causes and effects of adult thumb sucking and look at how someone can stop sucking their thumb.

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An adult may suck their thumb if they are feeling anxious or stressed.

There is no reliable data on how many adults suck their thumbs. However, thumb sucking is common in children. Research suggests that around 70%–90% of children suck their thumb.

Many babies also suck their thumbs, sometimes in utero. Most children will gradually stop sucking their thumbs as they get older, usually between the ages of 2–4.

Less commonly, thumb sucking will continue into the teenage years. For some, the habit can continue into adulthood.

Thumb sucking is a natural, instinctive behavior that provides comfort. Doctors call it a non-nutritive sucking habit. This is a group of soothing behaviors that also include the use of pacifiers or comfort blankets.

Babies and children begin sucking their thumbs as a reflex, making them feel secure and safe. The behavior may extend into adulthood for similar reasons. Adults may suck their thumbs as a response to stress or anxiety.

Thumb sucking could also be a response to trauma. Psychological trauma is a mental and physical response to events a person finds extremely stressful. According to the Substance Abuse and Mental Health Services Administration (SAMHSA), common examples include bullying, abuse, or a car accident.

According to Freudian psychoanalysis, a person who encounters challenging events may revert to an earlier stage of development as a way of coping. Psychologists call this age regression. Age regression involves a person adopting the behaviors of someone younger than themselves.

According to the Primary Care Companion for CNS Disorders, this could include behaviors such as:

  • cuddling stuffed animals
  • engaging in baby talk
  • sucking objects or body parts, such as the thumb

If a person’s thumb sucking is the result of trauma, they will also experience other signs of trauma, such as:

  • feeling alert, on edge, or unable to sleep
  • intense guilt, shame, anger, or panic
  • flashbacks to the traumatic event

Learn more about trauma types, symptoms, and treatments.

Thumb sucking in babies and children is generally harmless. However, excessive thumb sucking can lead to problems. According to a 2020 article, people who suck their thumb for long periods can develop certain health conditions.


Excessive thumb sucking can cause blisters on the thumb. Blisters are fluid-filled lumps that form under the skin. They usually occur when the skin is damaged.

It may be necessary to prevent thumb sucking while the blister heals. A band-aid can protect it from further damage. Avoid bursting the blister to reduce the risk of infection.


Keratin is a tough protein that hardens the skin. In hyperkeratosis, the skin forms additional layers of keratin, making it tough and hard. This can happen in response to the skin being repeatedly irritated.

Thumb sucking can irritate and put pressure on the skin, which can lead to calluses or corns. Hyperkeratosis can also lead to chronic skin conditions, such as eczema and psoriasis.

Tooth misalignment

Over time, thumb sucking can also lead to someone’s teeth moving out of alignment, according to the American Dental Association (ADA). Some people can also develop an overbite.

Dental problems are more common in those who suck their thumb more intensely. Having the thumb passively in the mouth is less likely to lead to tooth misalignment.

The methods that help a person stop sucking their thumb will depend on the cause. If they notice that they suck their thumb in times of stress or worry, addressing this may help.

A person could try:

  • replacing thumb sucking with a different stress-relieving activity, such as exercise or meditation
  • cognitive behavioral therapy (CBT) can help someone change specific beliefs that may contribute to their anxiety
  • other types of therapy, such as psychotherapy

The ADA suggest a variety of ways that a parent or caregiver can encourage a child to stop sucking its thumb. An adult can also try similar tactics, such as bandaging the thumb. This makes it difficult to suck, which can help reduce the behavior.

The National Institutes of Health (NIH) indicate that techniques that help people break other habits may also help someone who wants to stop thumb sucking, such as:

  • setting small goals, such as not sucking the thumb for one day, and then slowly building up
  • giving oneself rewards for each small milestone
  • mentally rehearse not sucking the thumb in situations that normally trigger the behavior
  • asking trusted friends, family, or coworkers for support

If someone is concerned about their thumb sucking habit, they may wish to talk to a doctor or therapist for advice. A dentist may also be able to help with any impact thumb sucking has on the teeth.

Many babies and young children suck their thumbs, but most stop by the age of 4. However, some people will continue to suck their thumb into adulthood. Vigorous thumb sucking can cause blisters, calluses, and dental problems.

Sucking their thumb may help an adult feel calm and reassured after experiencing stress or anxiety. Some people may suck their thumb in respsonse to trauma. Addressing the reasons behind the thumb sucking might help someone to stop.