Children and youth often display a cyclical pattern of aggression, outbursts of rage, long-standing thoughts of revenge, holding grudges, lying, stealing, bedwetting, hyperactivity, distractibility and extreme impulsivity. Rapid-cycling symptoms can be seen during sleep, in vivid, gory nightmares, restlessness, and insomnia. In addition, Mood Disorder in children may trigger severe reactions to authority figures and simple limit setting.

Hypersexuality, according to recent reports, is a distinguishing symptom of Early-Onset Bipolar Disorder. Sometimes a child will have been noted to have infrequent sexualized behaviors that were not aggressive or extensive. The presence of these incidents may serve as a warning, as bipolar children entering into puberty may experience their sexual interests as magnified or distorted, like their expressions of rage. Some children identified as sexually aggressive children may have been misdiagnosed, and have untreated Early-Onset Bipolar Disorder.

Unfortunately, the ability to attach to caregivers is also typical of Early-Onset Bipolar Disorder. This increases the likelihood that untreated children will be aggressive and violent, generate conflict in their homes, and fail to attach to their struggling parents.

Cycling fluctuations seen in Mood Disorders also impact the child's cognitive abilities. For instance, on one day the child can solve age appropriate problems, and several days later, be unable to even grasp the problem. Memory may also be impaired, especially working and short-term memory. This is common for children with ADHD and Early-Onset Bipolar Disorder, as clusters of neuropsychological problems often accompany behavior problems. The child's sense of pain may be greatly impaired, and many children have not exhibited a normal tolerance of pain.

Gross and fine motor problems, especially sensory integration impairments, are common and treatment with occupational therapy is helpful. The child may have impairment in visual tracking and visual convergence. A Visual Efficiency and Visual Processing Exam is recommended, where the child can be tested for visual and auditory processing impairments. About 30% to 40% of children with ADHD have deficits in visual or auditory processing.

Thyroid dysfunction, asthma, and allergies, including food sensitivities, are common in children with Mood Disorders, complicating diagnosis and treatment. Of critical importance is the possibility of hypoglycemia, which can be screened with a five-hour glucose tolerance test.

Learning disabilities are common, especially reading and math ability. This may be due to the fluctuating cognitive abilities, behavior problems in the classroom, or to sensory impairments. In more serious cases, a neuropsychological battery is recommended to determine the presence of organic damage, especially if a head injury at an early age, or of head-banging when younger. The neuropsychological battery will determine the cause and extent of the child's sensory impairment as well as the likelihood of success in further treatment.