BIPLONG - The Bipolar Disorder in the Longitudinal Course

Study Procedure:

In addition to the bipolar patients, healthy controls will also be included. The same inventories will be used for the control subjects and the same examinations or visits will be performed; bipolar-specific disease questions will not be asked in controls.

Intervention: Longitudinal study

Method:

All patients and controls undergo several assessments every six months:

Blood samples are collected with the following main parameters of interest being examined:

• Collection and analysis of DNA, establishment of permanent cell lines, determination of mRNA and gene products (proteins), proteomics, lipidomics.

• Routine parameters: Blood count, TSH, T3, T4, homocysteine, creatinine, amylase, lipase, CK, urea, uric acid, coagulation, HBA1c, glucose, lipids (triglyceryl, LDL, HDL, cholesterol, mass spectrometry), transaminases, CRP- levels, vitamin D.

• Biomarkers: oxidative stress parameters and antioxidants, neuroinflammatory markers (e.g. interleukins, tumor necrosis factor, interferons, GDNF, VEGF, etc.), neurotrophins (BDNF, NT, Trk..), insulin, IGF, adipokines, Apo-E and AAT analysis, tryptophan/kynurenine metabolites

• Intestinal hormones grehlin, glucagon-like peptides 1 and 2 (GLP-1/2) and cholecystokinin

Additionally, socio-demographic data and psychological data are collected by administering self-assessment questionnaires. Further, neurocognitive tests are administered.

The current psychological and psychiatric state of all subjects is examined by external ratings done by experts.

Anthropomethric measures are examined (waist-to-hip ratio, blood pressure, weight, height).

Additionally, MRI is conducted on all subjects (for patients every 6 months, for controls every 12 months).

Primary hypothesis:

• Gene-environment interactions are significantly contributory to bipolar affective disorder.

• There are pathologically altered neurobiological markers that play a role in the pathogenesis of bipolar disorder.

• There is an influence of anthropometric data on the course of bipolar disorder.

Statistical analysis and anticipated sample size:

Baseline data analysis will be investigated using a multi-factorial between subject design, with the variables of group (bipolar patients versus healthy controls), gender (males versus females), weight (normal weight versus overweight), etc. as independent factors, depending on the research question. As dependent variables, in addition to sociodemographic and clinical variables (number of episodes, etc.), physiological parameters (blood parameters, anthropometry and lipometer data, EEG, ECG, MRI) and psychological variables (psychological questionnaires) will be investigated. Likewise, covariates such as age or body mass index will be included as needed.

Correlation analyses (bivariate, partial) should show possible correlations between the variables. Discriminant analyses should find out which variable best separates the investigated groups (e.g. patients vs. controls). Furthermore, regression analyses (linear, multiple) will be performed to obtain additional information about the predictive value of the variables under investigation. All analyses will be computed using IBM SPSS Statistics 20.

For the "a priori analysis" of the follow-up study (T1-T5), a repeated measures design (repeated measures within factors) was adopted. The case number calculation (effect size d between .30 and .80; Cohen, 1988) for the F-test thus results in a sample size of 47 patients with a target effect size of .40 (power 95%; alpha .05; calculated with GPower 3.1). The correlation analyses at the first measurement time point (power .95, alpha .05, effect size: .35) yields 79 subjects per group (Pat. vs. controls) at all time-points.