Medical Health Encyclopedia

A 2003 study of Concerta indicated that depending on the ADHD subtype, children may require different doses. In the study, children with the inattentive type responded to lower doses than those with the combined type.

Side Effects. All stimulants have a number of side effects:

• The most common side effects of any stimulant are nervousness and sleeplessness, although some parents have reported improved sleep patterns in their children after taking stimulants.
• Children may lose weight.
• Tics or jerky, disordered movements occur in about 9% of children. Some studies indicate they are not caused by standard doses of Ritalin. In any case, low doses are often effective in controlling impulsivity without causing tics, even in some children who also have mild to moderate Tourette's syndrome.
• Other side effects include irritability, withdrawal, stomach pain, headache, depression, hallucinations, hair loss, and lack of spontaneity.

Of note, taking Ritalin with a high-fat breakfast may delay its effects.

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Symptoms of Overdose. Symptoms of overdose include changes in heart rhythm and rate, hypertension, confusion, breathing difficulties, sweating, vomiting, and muscle twitches. If they occur, parents should call the doctor immediately. Even among young people who abuse Ritalin, however, less than 1% experience severe side effects (rapid heart rate, hypertension) and outcomes are generally good. (Side effects may very severe, however, if Ritalin is overused and taken with other drugs.)

Long-Term Complications. Many people have taken Ritalin for years without experiencing adverse effects or loss of effectiveness. Few long-term complications have been reported, but the following warrant some caution or additional research:

• Early research had suggested that growth may be retarded during long-term treatment. Recent studies, however, have found little evidence for any significant growth suppression in boys or girls. In addition, a 2003 study found no significant effect on onset of puberty in girls.
• A 2001 study on animals suggested that there may be some long-term effects from methylphenidate that may change brain cell structure or function. Heavy abuse of other stimulants (cocaine, amphetamines) has been associated with worsening in motor skills and attention. However, more research is needed to determine if such changes occur with long-term use of Ritalin. In fact some evidence suggests that Ritalin may help increase white matter (the primary substance that makes up the core of the brain's hemispheres).