About 45 percent are non-compliant, an increase of 4 percentage points over 2012, according to scientists with research company GfK.
The most common reasons for noncompliance, according to prescribing physicians, include dislike of the medication, concern about side effects and the denial of illness, researchers report.
Since 2009, the level of noncompliance among schizophrenia patients has ranged from 41 percent to 46 percent, according to the annual study, now in its 17th year.
This year, 74 percent of psychiatrists mentioned patient dislike of medications as a reason for non-compliance.
Another 71 percent of patients cited side effects, including extrapyramidal symptoms (EPS), tremors, sleepiness and weight gain.
Extrapyramidal symptoms include involuntary asymmetrical movements of the muscles, neck spasms, and a feeling of motor restlessness. These types of symptoms are typical among people who take the most commonly-prescribed medications for schizophrenia.
While “depot” drugs — taken once a week or less by injection by a healthcare professional — are the most talked-about new development in the treatment of schizophrenia, they have not substantially improved compliance, according to the researchers.
They found that depot drugs account for about 20 percent of all schizophrenia prescriptions, up just slightly from last year. Only 2 percent of doctors surveyed expect to “significantly increase” their use of depot drugs to treat schizophrenia in the next six months, the researchers report.
The study also shows a variety of unmet needs among the current crop of schizophrenia treatments. Psychiatrists would like to see better control of negative and cognitive symptoms, fewer metabolic side effects, and improvement in cognitive deficits, according to the study’s findings.
“Drug manufacturers need to address the top unsatisfied requirements among psychiatrists, and even market to those benefits,” said Paul Wojciak, research director on GfK’s health team.
“As more doctors become familiar with the benefits of depot drugs, we may see a shift in how schizophrenia is treated in the coming years.”
Monthly schizophrenia patient volume has remained relatively stable since 2011, accounting for about 30 percent of psychiatrists’ overall practice, according to the recently released study.
Schizophrenia patients are almost twice as likely to be seen in a community mental health center (46 percent) as at a private office (26 percent). Another 17 percent receive inpatient treatment at a hospital, either general or psychiatric, according to the study.