Scientists from Denmark tracked how mood affects the intimate lives of people with bipolar disorder, a mental illness in which periods of elevated and depressed mood alternate with relatively calm intervals. The work was published in the Journal of Psychiatric Research.
The study involved 236 people aged 18 to 68. All had been diagnosed with bipolar disorder no more than two years earlier. Over six months, participants attended clinical visits three times: at the start, after three months and after six months. Doctors assessed the severity of depressive and manic symptoms using standard scales, and participants themselves filled out questionnaires about sexual desire and sex-related experiences. In addition, every day they recorded their mood in a special smartphone app on a nine-point scale.
It turned out that the more severe the depressive symptoms, the lower the sexual desire. This association persisted even after questions directly concerning sexual interest were removed from the scales. However, the initial association between the severity of manic symptoms and increased desire ceased to be statistically significant after this check. The researchers suggest it may have been an artifact, that is, a side effect of the fact that questions about sex overlapped within the questionnaires themselves, rather than an independent effect of mania.
Separately, the scientists looked at sexual distress, which is the feeling of awkwardness, disappointment, anxiety or upset that a person experiences because of problems in their sex life. It differs from purely physical dysfunction. It turned out that the higher the level of depression, the more pronounced such distress. A higher overall quality of life, by contrast, was associated with less worry about sex. Manic symptoms were not associated with sexual distress: possibly, increased desire during such periods is not perceived by a person as a problem.
Smartphone data showed another pattern: the more variable mood was from day to day, the higher the sexual distress. This refers to everyday mood fluctuations outside severe episodes of the illness. This is a correlation, a statistical association that in itself does not prove that mood swings cause distress.
The authors note that differences between people were very large: roughly two-thirds of the variance in measures of desire and distress was explained by individual characteristics of the participants. Only about 16% of participants met the criteria for sexual dysfunction, noticeably fewer than in previous studies, which cited figures as high as 50%. The researchers attribute this to the limitations of the work: people taking selective serotonin reuptake inhibitors (SSRIs), common antidepressants that often produce sexual side effects, were excluded from it. In addition, participants were concurrently enrolled in another clinical trial, which required organization and may have attracted people with a milder course of the illness. Finally, only recently diagnosed patients were studied, so the results may not extend to those who have lived with bipolar disorder for many years.