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Bipolar disorder is a severe psychiatric syndrome defined by periodic mood shifts. Patients with bipolar disorder show cognitive impairments relative to healthy controls. The risk of developing schizophrenia, and partially also bipolar disorder, has previously been shown to increase with lower premorbid intelligence. It is not known if premorbid intelligence is associated with level of functioning and illness severity of people having developed bipolar disorder.We used multiple linear and ordinal regression to analyze how premorbid intelligence, as measured at conscription, associate with functional outcome and illness severity in Swedish male bipolar disorder patients (n = 788).We found that lower premorbid intelligence is associated with lower percentage of time in work, after adjusting for age and bipolar subtype, and correcting for multiple comparisons. We also found a strong negative association with the total number of inpatient episodes and psychiatric comorbidity, but not with interepisodic remission, treatment with psychotherapy or lithium or the presence of any complicating socioeconomical factors. Adjusting for confounding genetic factors using polygenic risk scores for bipolar disorder and schizophrenia had no effect on the associations.This study lacks females and controls and may thus have lower generalizability.In conclusion, premorbid intelligence is associated with both level of functioning and illness severity as well as comorbidity in bipolar disorder patients. Further research is needed to develop targeted interventions for this subgroup of bipolar disorder patients.

To investigate external factors that trigger manic and hypomanic relapses and how this is associated with personality and clinical outcome measured as number of affective episodes over a seven-year period.This is a prospective cohort study of 204 meticulously characterized Swedish bipolar disorder patients. Personality was evaluated at baseline using the Swedish universities Scales of Personality in 170 patients, and 90 patients were followed up after approximately seven years in order to evaluate clinical outcomes.We found that 44% of the patients reported trigger factors, including sleep disturbance, work or family related issues, medication, and illicit drug use. There were no significant differences in any of the personality traits when comparing the 74 patients that reported triggers with the 90 patients that did not. At seven-year follow-up, there was no difference between the groups in number of affective episodes (depressive, hypomanic, manic or mixed), involuntary commitments, suicide attempts, or self-harm incidents since baseline.Around 40% of the patients reported external triggers for manic and hypomanic episodes. However, this was neither associated with personality traits nor number of affective episodes at seven-year follow-up.Around 40% of all bipolar disorder patients reported trigger factors for manic or hypomanic episodes. Reporting trigger factors was not associated with personality Reporting trigger factors was not associated with outcomes over a seven-year period. Limitations Patients had on average long duration of illness and may be less sensitive to external stressors than persons with recent onset. Trigger factors were identified retrospectively, and may thus be prone to recall bias. The number of affective episodes might be a too crude outcome measure as most subjects had not suffered any affective episodes at follow-up.

The pathophysiology of bipolar disorder remains to be elucidated and there are no diagnostic or prognostic biomarkers for the condition. In this explorative proteomic study, we analyzed 201 proteins in cerebrospinal fluid (CSF) from mood stable bipolar disorder patients and control subjects sampled from two independent cohorts, amounting to a total of 204 patients and 144 controls. We used three Olink Multiplex panels, whereof one specifically targets immune biomarkers, to assess a broad set of CSF protein concentrations. After quality control and removal of proteins with a low detection rate, 105 proteins remained for analyses in relation to case–control status and clinical variables. Only case–control differences that replicated across cohorts were considered. Results adjusted for potential confounders showed that CSF concentrations of growth hormone were lower in bipolar disorder compared with controls in both cohorts. The effect size was larger when the analysis was restricted to bipolar disorder type 1 and controls. We found no indications of immune activation or other aberrations. Growth hormone exerts many effects in the central nervous system and our findings suggest that growth hormone might be implicated in the pathophysiology of bipolar disorder.

Variation in the CACNA1C gene has been associated with bipolar disorder in several genome-wide association studies. This gene encodes the alpha 1C subunit of L-type voltage-gated calcium channels, which play an essential role in neurons. We analysed 39 biomarkers in either cerebrospinal fluid or serum in relation to six different CACNA1C variants in 282 patients with bipolar disorder and 90 controls. We report associations of CACNA1C risk alleles with serum levels of BDNF as well as tissue plasminogen activator, which converts pro-BDNF to mature BDNF. This sheds light on links between CACNA1C genetic variants and pathophysiological mechanisms in bipolar disorder.