In the United States, 1.1 percent of adults have schizophrenia and 4.1 percent of adults have ADHD, according to the National Institute of Mental Health. Patients with these disorders may have difficulty functioning. For example, the hyperactivity and inattention symptoms of ADHD may interfere in school work. With schizophrenia, patients have difficulty determining what is real and what is not real. While both of these conditions may cause problems for patients, different types of medications and therapies can help.
Different types of ADHD and schizophrenia exist. The National Institute of Mental Health defines three types of ADHD, which differ based on their symptoms. For example, a patient with inattentive ADHD has six or more inattention symptoms, while a patient with hyperactive-impulsive ADHD has six or more hyperactive and impulsive symptoms. With the third type of ADHD, combined ADHD, patients have six or more hyperactive-impulsive symptoms and six or more inattention symptoms.
MedlinePlus lists five different types of schizophrenia: catatonic schizophrenia, paranoid schizophrenia, disorganized schizophrenia, residual schizophrenia and undifferentiated schizophrenia. Patients with undifferentiated schizophrenia have symptoms of more than one type, such as rigid muscles from catatonic schizophrenia, becoming argumentative from paranoid schizophrenia and childlike behavior from disorganized schizophrenia. Residual schizophrenia patients do not have as many symptoms as patients with other types of schizophrenia.
Some ADHD patients have a higher risk of developing schizophrenia. In the article "Schizophrenia Risk Rises When Child has ADHD Plus Relative with Disorder," Joan Arehart-Treichel explains that patients with ADHD who have either a sibling or parent with schizophrenia have a higher risk of developing schizophrenia later in life. The study looked at 29 people who had a schizophrenic relative and 30 people who do not have a schizophrenic relative. Nine of the participants who had a schizophrenic relative fulfilled the diagnostic criteria for ADHD. Those nine participants had higher scores on tests for neurological schizophrenia signs when compared to the controls and to participants who did not have ADHD but had a schizophrenic relative.
Schizophrenia and ADHD have different ages of onset. With schizophrenia, the age of onset varies by gender. The National Institute of Mental Health explains that women start to show signs of schizophrenia while in their 20s or early 30s, while men start to show signs while in their late teen years and early 20s. The symptoms of ADHD start much younger. The National Institute of Mental Health notes that children start to show symptoms between the ages of 3 and 6, though the symptoms can continue into adulthood.
Patients with ADHD and schizophrenia may take medications to control their symptoms. MedlinePlus points out that stimulant medications, such as amphetamine-dextroamphetamine, are the most common prescribed medication for the disorder. Another option is a non-stimulant medication called atomoxetine. With schizophrenia, medications called antipsychotics may help with the symptoms of the disorder. The National Institute of Mental Health breaks the antipsychotics into two groups: typical antipsychotics, such as haloperidol, and atypical antipsychotics, such as olanzapine. Some patients may benefit from non-pharmacological treatments. For schizophrenia and ADHD patients, social skills training may help them with social functioning. ADHD patients may also benefit from behavior therapy, which teaches them how to control their impulsive and hyperactive behaviors.
Without proper treatment, ADHD and schizophrenia may lead to other problems. For example, MedlinePlus notes that both ADHD and schizophrenia patients may develop a substance abuse problem, which requires treatment. Untreated ADHD may lead to problems in school and work. If schizophrenia patients do not take their medications, they may start having symptoms such as hallucinations and delusions again.