What are Mood Disorders?
- Mood disorders are characterized by pathological alterations in one’s mood, energy, and activity levels, significantly affecting daily functioning.
- Major Depressive Disorder (MDD): Persistent sadness, loss of interest in activities, fatigue, cognitive difficulties, feelings of hopelessness, and suicidal thoughts.
- Bipolar Disorder: Involves extreme mood fluctuations between depression and mania, the latter being characterized by elevated mood, increased energy, decreased need for sleep, and impulsivity.
Causes of Mood Disorders
- The genesis of mood disorders is multifactorial and influenced by a combination of genetics and environmental factors.
- Genetic vulnerability: Mood disorders, particularly bipolar disorder, tend to run in families. The genetic contribution to bipolar disorder is significant, with heritability ranging between 60-85%.
- Gene-environment interactions: Environmental stressors, such as childhood abuse, trauma, financial difficulties, and significant life events, interact with genetic predispositions, influencing the onset of mood disorders.
- Proximal stressors: Include adverse childhood experiences like abuse, neglect, or domestic violence.
- Distal stressors: Include adulthood challenges such as financial difficulties, bereavement, and trauma.
The Role of Chronic Stress
- Chronic stress leads to HPA axis dysregulation, where the body’s response to stress (via cortisol release) remains active even after the stressor ends, leading to a chronic low-grade inflammatory state.
- Bipolar disorder is particularly sensitive to stress, with depressive relapses linked to negative life events and manic relapses associated with goal-attainment events.
Circadian Functioning in Bipolar Disorder
- Bipolar disorder is closely linked to disruptions in the circadian system, which regulates the body’s internal clock. Circadian rhythms such as body temperature and melatonin secretion often become disrupted during mood episodes.
- The relationship between these disturbances and mood dysfunction is still under study, as researchers are unsure whether these circadian disruptions cause or result from mood disorders.
Diagnostic Challenges
- Bipolar disorder often begins with depressive episodes, and it can take 6 to 10 years from the first symptoms to an accurate diagnosis.
- Hypomanic episodes may go unnoticed because individuals may not seek help during these phases, sometimes enjoying the elevated mood.
- Clinicians look for:
- Early-onset depression.
- Family history of bipolar disorder.
- Unusual responses to antidepressants.
- Substance misuse or attention deficit disorder.
Bipolar disorder and other mood disorders are complex and multifactorial. While genetic factors play a significant role, environmental stressors and disruptions in circadian rhythms also contribute to the onset and progression of these disorders. Early recognition and intervention are critical, and with appropriate treatment, individuals with mood disorders can lead fulfilling, productive lives.
