Introduction. Hyperkinetic disorder or attention-deficit hyperactivity
disorder (ADHD) is a clinical entity consisting of a cluster of symptoms
including hyperactivity, attention disorder and impulse control disorder
group. In the context of ADHD etiology we may say that genetic, clinical and
imaging studies point out a disruption of the brain dopamine system, which is
corroborated by the clinical effectiveness of stimulant drugs, which increase
extracellular dopamine in the brain. Basically, it is a biological and not
psychological disorder, which is important both for the comprehension and
therapeutical approach to this problem. Today, the best recommended approach
regarding children with ADHD is a combination of two therapeutic modalities:
pharmacotherapy and behavioral treatment. The first-choice drugs for this
disorder belong to the group of sympathomimetics - psychostimulants and
atomoxetine (more recently). As the firstchoice therapy, methylphenydate in
sustained release form has numerous advantages. Like all drugs,
methylphenidate has its unwanted side effects. Most common are: loss of
appetite, weight loss, sleeping disorders, irritability, headache. These side
effects are well-known and documented in the literature. By analysing the
available literature we have found cases of psychiatric side effects such as:
psychosis, mania, visual hallucinations, agitation, suicidal ideas. We have
not found examples of ADHD in children who use increased dosage of sustained
release of methylphenidate leading to depressive symptomatology. On the other
side, methylphenidate may be prescribed for off-label use in
treatmentresistant cases of depression. Case report. The case of a 7-
year-old boy diagnosed with ADHD was on a minimal dose of sustained release
form of methylphenidate. After initial titration of the drug, i.e. after
raising the dose to the next level the boy developed clinical signs of
depression. The treatment was ceased and depressive symptoms were withdrawed.
Conclusion. Manifestation of depressive symptomatology after dose
increasement of sustained release form of methylphenidate in a 7-year-old boy
with ADHD represents an uncommon side effect. Precise drug activity
mechanisms responsible for the appearance of these symptoms remains to be
explained.