The temporal dynamics of mood and their association with depressive symptoms in Huntington's disease

Background: Huntington's disease (HD) is an inherited neurodegenerative disorder characterised by progressive motor abnormalities, cognitive decline, and neuropsychiatric disturbances. Depression is among the most common neuropsychiatric syndromes in HD. Research in neurologically healthy samples has shown that depression is associated with distinct patterns of short-term fluctuations in mood, which may exacerbate negative effects on psychological wellbeing. The short-term dynamics of mood and their relationship with depression have not yet been investigated in HD. Methods: Fifty-five adults with the HD CAG expansion (33 pre-manifest, 22 manifest) completed single timepoint measures of depression, demographic factors, and clinical disease outcomes on day 1, then rated their mood daily for 28 consecutive days. Average mood, mood variability, and mood inertia (auto-correlation) were calculated across the 28 days. Results: Depression severity on day 1 was significantly associated with average mood across the 28 days, but not with day-to-day mood variability or inertia. Additionally, female HD CAG expansion carriers experienced more day-to-day variability in mood compared to males. Limitations: Our sample did not include HD CAG expansion carriers with severe depressive symptoms or advanced HD, which limits the generalisability of the findings. Additionally, findings may have been affected by antidepressant and antipsychotic medication use among many participants. Conclusions: In HD, short-term patterns of change in mood appear to be relatively independent of depression severity. Moreover, in female CAG-expansion carriers particularly, mood variability may warrant further clinical attention. These findings should be replicated in larger and more diverse samples, with different timescales and measures for assessing mood.