A habit is a strong behaviour pattern that is repeated over and over again. Habits may develop as entertainment for a bored child or, more commonly, as a coping mechanism to soothe anxiety. Sucking is a normal phenomenon in early occasional infancy.

Thumb sucking when the child is hungry, disturbed and lonely, or is satisfying his urge for sucking, is a perfectly acceptable and normal phenomenon in children less than a year old.

In infants, thumb sucking is a common self-comforting behaviour that has pleasurable associations with feedings and cessation of hunger. The behaviour may linger into childhood because of these positive associations.

A hungry child may not only put his thumb, but his whole hand into his mouth. Sometimes the child is able to finish his bottle very quickly and since he has nothing else to do, he sucks his thumb. This is because sucking is soothing and comforting.

Usually babies who are breastfed are less likely to suck their thumbs than those who are bottle-fed. This is because a baby gets his milk more quickly through a bottle and is not able to fully satisfy the sucking urge. So he resorts to thumb sucking. A breastfed baby may also suck his thumb if his sucking instinct is not fully satisfied. Children who have not sucked their thumb before they are a year old, seldom do it later.

It is perfectly normal for a young child to suck her thumb or bite her nails. Sucking the thumb for a little while when falling asleep or when the child is tired should be allowed. Most school children have these habits. These unconscious, nervous habits are usually caused by tension. Do not try to stop your child through force or ridicule. The child will learn self control by herself, as she grows older. She will become more conscious of her appearance and learn socially appropriate behaviour.

Calmly point out what you don't like about the behaviour and why. This approach can be used with children as young as three. Do not scold or lecture her. Punishment, ridicule, or criticism could cause the behaviour to worsen.

Involve the child in the process of breaking the habit. Ask your child what she thinks she could do to stop the habit or if she wants to stop the habit.

Children have a lot of energy. Give them paper, pencil, clay or mud for modelling, building blocks and other things to do. This will keep them occupied. If, after the age of five, a child sucks his thumb frequently without any obvious reason, consult your doctor for a check-up and then perhaps take the child to a child psychologist.

To help a child quit thumb sucking, the first step is to ignore them! Most often, it will disappear with time. Harsh words, teasing, or punishment may upset the child, and the habit will get worse. Punishment is not an effective way to get rid of habits. Older children (more than 3 years of age) may use sucking to relieve boredom. Try getting the child's attention with an activity that he finds interesting. Rewarding good behavior is the best way to bring about change. Praise and reward the child when she does not suck her thumb or use the pacifier.

If the above measures do not work, a paediatrician might recommend trying a reminder such as covering the thumb with a plastic strip or "thumb guard" which is an adjustable plastic cap that is taped to the thumb. The child should be directly involved with the treatment chosen. Before using these methods, be sure to explain them to the child. If they make the child afraid or tense, stop them at once.

A vigorous thumb-sucker can harm her teeth - the upper teeth will protrude forward while the lower tend to be drawn inwards or backwards. Since this habit is mainly in children under five years of age and the harm is done primarily to the milk teeth, one need not worry too much about it. However if this habit persists beyond the age of five, the permanent teeth will also be affected, leading to expensive dental treatment for malformed teeth.

Most habits are self-limiting and do not require professional help. But if the habit affects your child's physical or social functioning or persists even after you have tried all possible techniques, the behaviour may have a more serious emotional or physical cause. In these situations, you should consult your paediatrician or a mental health professional.