Personality disorders and substance use disorders, conditions that frequently occur together, can be highly debilitating. The mortality rate for a person with both conditions is 10 to 15 times higher than for a person with neither condition.
In an article titled “What’s Old is New Again: Updated Findings on Personality Disorders and Substance Use Disorders” published in the journal Current Opinion in Psychiatry, University of Florida researchers review the state of the science on the prevalence, biological and behavioral pathways, and treatments for co-occurring personality and substance use disorders.
“Personality disorders and substance use disorders have been linked since the first edition of the Diagnostic and Statistical Manual of Mental Disorders came out in 1952. In that definition, substance use disorders were considered a part of personality disorders. The definitions have changed since then, but the strong relationship between the two has not,” said lead author Mr. Nathan Smith, a doctoral student in epidemiology in the UF College of Public Health and Health Professions and the UF College of Medicine.
Mr. Smith authored the paper with his mentor, Dr. Linda B. Cottler, a dean’s professor of epidemiology and PHHP’s associate dean for research.
For the UF study, the researchers evaluated 39 recent studies on personality and substance use disorders. The presence of both disorders can complicate treatment, but these disorders are treatable, and new and better treatments are being developed all the time, Mr. Smith said.
“We report on a number of promising interventions that are already under development,” Mr. Smith said. “While the future might be genetic or pharmaceutical interventions, the current talk therapies can be very effective.”
Co-occurring personality and substance use disorders are more common in incarcerated populations than in the general population, according to several studies from the U.S. and other countries.
“I think the next step is to look deeply into some of the sub-populations where these conditions are more common,” Mr. Smith said. “How can the field improve the lives of military veterans or incarcerated people? This is an important question.”
Evidence from international and domestic studies suggests that possible shared pathways between personality disorders and substance use orders may include emotional dysregulation, shared genes and certain neurotransmitters.
In psychiatric epidemiology it is important to always look back at the history of the field in order to anticipate what is coming next, Mr. Smith said.
“The field has moved from the inclusion of only people in psychiatric institutions a hundred years ago to now when many studies do not include people who are institutionalized at all,” he said. “For studies of personality disorders, the inclusion of people who are institutionalized is critical. We rely on the work of the scientists that have come before us to help design the studies that will take us forward.”
When trying to identify the presence of psychiatric symptoms of substance use disorder or personality disorders, the questions are the key, Mr. Smith said.
“The fundamental ingredients in good psychiatric epidemiology have not changed,” he said. “Recruit a representative sample. Ask valid and reliable questions. Avoid confounding and bias. If these fundamental pillars of the study are not strong, then the whole study crumbles.”