Bipolar disorder is a complex mental health condition characterized by dramatic and unpredictable changes in mood, attitude, and energy levels. Untreated bipolar disorder can undermine a person’s ability to live a satisfying life and elevate their risk for premature death. That’s why effective, evidence-based treatment for bipolar disorder is essential.
Typically, the symptoms of bipolar disorder become apparent before a person reaches age 30. However, recently published research indicates that this disorder may also have profound negative effects that do not become evident until after people pass their 50th birthday.
Age, Cognition, & Bipolar Disorder
According to a cross-sectional analysis in the December 2022 edition of the journal Psychological Medicine, bipolar disorder can contribute to accelerated cognitive decline in older adults.
The research team included researchers from the University of Toronto, the Centre for Addiction and Mental Health (which is also located in Toronto), and the University of Pittsburgh. Here’s how they designed the study:
- 315 participants
- 118 people who had bipolar disorder and 197 subjects who had not been diagnosed with any mental illnesses.
- Participants include control groups and bipolar disorder groups, divided into two age-based groups
- One for study participants ages 49 and under
- One for subjects ages 50 and above.
- Researchers assessed groups for overall cognition as well as abilities in seven cognitive domains:
- Processing speed
- Executive function/working memory
- Verbal memory
- Visual spatial memory
- Reasoning/problem solving
- Social cognition.
- Researchers administered a “comprehensive neuropsychological battery” of assessments that included:
- MATRICS Cognitive Consensus Battery
- Trail Making Test B
- Stroop Test
- Wechsler Test of Adult Reading, and eight additional tests.
After analyzing the test results and other data, researchers engaged in a close analysis of the results. They reviewed data on four groups:
- Younger patients with bipolar disorder
- Older patients with bipolar disorder
- Younger control group, no bipolar disorder
- Older control group, no bipolar disorder
Here’s what they found.
Results: Cognitive Decline and Bipolar Disorder Among Older Adults
- Older people with bipolar disorder showed accelerated effects of aging in three cognitive domains
- Processing speed
- Executive function/working memory.
- The younger bipolar disorder groups demonstrated early impairment in the verbal memory domain.
- Severity of a person’s bipolar disorder did not impact cognitive performance, as measured by:
- History of psychosis
- Number of depressive episodes
- Frequency of hospitalization
The researchers reported that all the study participants with bipolar disorder participated in treatment for bipolar disorder, and all took some type of prescription medication to help manage their symptoms. They cited this as a limitation in their study. Research shows the mood stabilizers, antipsychotics, and other medications commonly used to treat BD negatively impact cognitive performance.
Other Possible Causes of Cognitive Decline
About 17 months before the research discussed in the previous section appeared in Psychological Medicine, the journal Acta Psychiatrica Scandinavica published a similar study.
This study, conducted by a research team in The Netherlands, assessed a broader range of potential causes of cognitive decline. It explored how influences such as symptom severity, psychotropic medications, and cardiovascular risk factors may impact the cognitive capabilities of older adults with bipolar disorder, including adults who had participated in any form of bipolar disorder treatment.
Study Design: How Researchers Assessed Patients With BD
- The Dutch researchers collected data from 172 adults aged 50 or above, all of whom had been diagnosed with bipolar disorder and participated in some type of bipolar disorder treatment
- Symptom severity and use of psychotropic medications were identified via questionnaires and interviews.
- Cardiovascular risk factors were identified through interviews, physical exams, and lab tests.
- The subjects were assessed via 13 tests that focused on four cognitive domains: attention, learning/memory, verbal fluency, and executive functioning.
Study Results: What the Research Team Found
- The three strongest influences on subjects’ cognitive abilities were age of onset of bipolar disorder symptoms, number of psychiatric admissions, and use of benzodiazepines.
- Subjects who had late-onset bipolar disorder demonstrated better cognitive performance.
- Subjects who had more than five psychiatric admissions demonstrated a greater degree of overall cognitive impairment. These individuals scored particularly low in the domain of executive functioning.
- Current benzodiazepine use was also associated with poor performance on the cognitive assessments.
- Metabolic syndrome (which includes several symptoms that can increase a person’s risk for heart disease, stroke, and type-2 diabetes) has a greater influence on a person’s cognitive functioning than does their body mass index (BMI).
The team determined that the number of manic, hypomanic, and depressive episodes a person had did not significantly impact their later-life cognitive capabilities.
Surprisingly, the team also found that lifetime smoking was associated with a higher composite score on the cognitive assessments. They noted that this finding is counterintuitive, and that it contradicts previous research that links lifetime smoking with increased rates of dementia. They theorized that this may indicate an anomaly among the individuals who were selected for the study.
Calls for Additional Research
Both of the teams whose findings are described in this post called for additional research into the causes and effects of cognitive decline among older adults with bipolar disorder. This research, they noted, could help determine the rate of cognitive decline, identify biomarkers that may offer greater insights into the causes of this accelerated decline, and suggest new types of treatment.
The Dutch team described the value and necessity of additional study in the following manner:
“Future research should study (combinations of) determinants of cognitive functioning in further detail,” they wrote. “For example, it is important to study these relationships in different phases of [borderline personality disorder] and in different age groups. Also, the influence of the dosing of psychotropic medication on cognition could be a topic of further (longitudinal) studies.”