Influence of birth cohort on age of onset cluster analysis in bipolar I disorder

Purpose:

Two common approaches to identify subgroups of patients with bipolar disorder are clustering methodology (mixture analysis) based on the age of onset, and a birth cohort analysis. This study investigates if a birth cohort effect will influence the results of clustering on the age of onset, using a large, international database.

Methods:

The database includes 4037 patients with a diagnosis of bipolar I disorder, previously collected at 36 collection sites in 23 countries. Generalized estimating equations (GEE) were used to adjust the data for country median age, and in some models, birth cohort. Model-based clustering (mixture analysis) was then performed on the age of onset data using the residuals. Clinical variables in subgroups were compared.

Results:

There was a strong birth cohort effect. Without adjusting for the birth cohort, three subgroups were found by clustering. After adjusting for the birth cohort or when considering only those born after 1959, two subgroups were found. With results of either two or three subgroups, the youngest subgroup was more likely to have a family history of mood disorders and a first episode with depressed polarity. However, without adjusting for birth cohort (three subgroups), family history and polarity of the first episode could not be distinguished between the middle and oldest subgroups.

Conclusion:

These results using international data confirm prior findings using single country data, that there are subgroups of bipolar I disorder based on the age of onset, and that there is a birth cohort effect. Including the birth cohort adjustment altered the number and characteristics of subgroups detected when clustering by age of onset. Further investigation is needed to determine if combining both approaches will identify subgroups that are more useful for research.

Trajectories of adherence to mood stabilizers in patients with bipolar disorder

Background

Nonadherence with mood stabilizers is a major problem that negatively impacts the course of bipolar disorder. Medication adherence is a complex individual behavior, and adherence rates often change over time. This study asked if distinct classes of adherence trajectories with mood stabilizers over time could be found, and if so, which patient characteristics were associated with the classes.

Methods

This analysis was based on 12 weeks of daily self-reported data from 273 patients with bipolar 1 or II disorder using ChronoRecord computer software. All patients were taking at least one mood stabilizer. The latent class mixed model was used to detect trajectories of adherence based on 12 weekly calculated adherence datapoints per patient.

Results

Two distinct trajectory classes were found: an adherent class (210 patients; 77%) and a less adherent class (63 patients; 23%). The characteristics associated with the less adherent class were: more time not euthymic (p < 0.001) and female gender (p = 0.016). No other demographic associations were found.

Conclusion

In a sample of motivated patients who complete daily mood charting, about one quarter were in the less adherent class. Even patients who actively participate in their care, such as by daily mood charting, may be nonadherent. Demographic characteristics may not be useful in assessing individual adherence. Future research on longitudinal adherence patterns in bipolar disorder is needed.

Solar insolation in springtime influences age of onset of bipolar I disorder

OBJECTIVE

To confirm prior findings that the larger the maximum monthly increase in solar insolation in springtime, the younger the age of onset of bipolar disorder.

METHOD

Data were collected from 5536 patients at 50 sites in 32 countries on six continents. Onset occurred at 456 locations in 57 countries. Variables included solar insolation, birth-cohort, family history, polarity of first episode and country physician density.

RESULTS

There was a significant, inverse association between the maximum monthly increase in solar insolation at the onset location, and the age of onset. This effect was reduced in those without a family history of mood disorders and with a first episode of mania rather than depression. The maximum monthly increase occurred in springtime. The youngest birth-cohort had the youngest age of onset. All prior relationships were confirmed using both the entire sample, and only the youngest birth-cohort (all estimated coefficients P < 0.001).

CONCLUSION

A large increase in springtime solar insolation may impact the onset of bipolar disorder, especially with a family history of mood disorders. Recent societal changes that affect light exposure (LED lighting, mobile devices backlit with LEDs) may influence adaptability to a springtime circadian challenge.

Regularity in daily mood stabilizer dosage taken by patients with bipolar disorder

OBJECTIVE

The aim of this study was to investigate regularity in the daily mood stabilizer dosage taken by patients with bipolar disorder, and identify factors associated with irregularity.

METHODS

Self-reported daily mood and medication data were available from 206 patients who took the same mood stabilizer for ≥100 days. Approximate entropy (ApEn) was used to measure serial regularity in daily mood stabilizer dosage. Generalized estimating equations (GEE) were used to estimate if demographic or clinical variables were associated with ApEn.

RESULTS

There was a wide range of regularity in the daily mood stabilizer dosage. The mean percent of days of missing doses was 13.6%. The number of psychotropic medications (p=0.007), pill burden (p=0.004) and percent of days with depressed mood (p=0.013) were associated with more irregularity, while the percent of days euthymic (p=0.014) was associated with less irregularity. The percent of days missing doses was not associated with the number of medications, pill burden or mood ratings.

DISCUSSION

Patients may have irregularity in daily dosage in spite of a low percent of days missing doses. Psychotropic medication regimen complexity and depression are associated with increased dosage irregularity. Research is needed on how irregularity in daily dosage impacts the continuity of drug action of mood stabilizers.

Prospective 12-month course of bipolar disorder in out-patients with and without comorbid anxiety disorders

BACKGROUND

The impact of anxiety disorders has not been well delineated in prospective studies of bipolar disorder.

AIMS

To examine the association between anxiety and course of bipolar disorder, as defined by mood episodes, quality of life and role functioning.

METHOD

A thousand thousand out-patients with bipolar disorder were followed prospectively for 1 year.

RESULTS

A current comorbid anxiety disorder (present in 31.9% of participants) was associated with fewer days well, a lower likelihood of timely recovery from depression, risk of earlier relapse, lower quality of life and diminished role function over I year of prospective study. The negative impact was greater with multiple anxiety disorders.

CONCLUSIONS

Anxiety disorders, including those present during relative euthymia, predicted a poorer bipolar course. The detrimental effects of anxiety were not simply a feature of mood state. Treatment studies targeting anxiety disorders will help to clarify the nature of the impact of anxiety on bipolar course.

A comparison of the restraint and seclusion experiences of patients with schizophrenia or other psychotic disorders

OBJECTIVE

The purpose of this study was to understand how restrained and secluded patients felt about these interventions, and to compare the perceptions of the two groups.

METHODS

Subjects were 25 restrained, and 25 secluded inpatients. A questionnaire was developed to explore patients' feelings and perceptions of the two interventions. Comparisons were made on the clinical data and the answers from both groups.

RESULTS

Restrained and secluded patients seemed to view some aspects of their experience differently. Few (40%) of the secluded group reported finding positive aspects, compared to even fewer (20%) of restrained. Most patients in both groups felt negatively about staff involved, and disagreed with staff on the reported intensity of their documented threatening behavior. The interventions seemed to have only a brief modifying effect on patients' behavior following these interventions and did not seem to modify future behavior.

CONCLUSIONS

Despite their differences, many patients in both groups reported negative feelings about the interventions and the staff involved. Both groups seemed not to perceive the procedural staff interactions as communication. Our study population seemed to be a subgroup of the admitted patient population who were repeatedly requiring seclusion or restraint. Screening this patient population during the admission process, and planning preventive and alternative interventions could decrease the need for restraint and seclusion.

The etiology of panic disorder: a review of current research

During the last decade, there has been extensive research toward understanding the etiology and developing a treatment approach for panic disorder. This is a review and summary of issues related to proposed current biological mechanisms in an attempt to define the etiology of panic disorder. It also emphasizes the need for further studies.

The effect of intensive case management on hospitalization of patients with schizophrenia

OBJECTIVE

The study aim was to determine if a community-based psychiatric rehabilitation program with intensive case management was more effective than traditional outpatient services in reducing hospitalization of chronic schizophrenic patients.

METHODS

One hundred twelve schizophrenic patients enrolled in the intensive case management program were matched by age, number of previous hospitalizations, and days spent in the hospital with 112 schizophrenic patients who received medication services and minimal case management. The two groups were compared on the amount of services used and the number of hospitalizations and hospital days over a 24-month study period.

RESULTS

Patients in the intensive case management program had been enrolled for a mean of 10.96 months, with a range from one to 24 months. They used significantly more mental health services during the study period compared with the patients in the control group. However, no significant differences were found between the two groups in number of hospitalizations and hospital days. Both groups showed an increase in the number of hospitalizations over the study period.

CONCLUSIONS

A community-based psychiatric rehabilitation program with intensive case management was no more effective than medication services and minimal case management in reducing hospitalization among chronic schizophrenic patients.