Bipolar disorder
Persons experiencing periods of hypomania or mania
Hypomania
Characterized by a reduced need for sleep, high energy, and positive affect. During periods of hypomania, people are talkative, energetic, impulsive, positive, and very confident. In this state, they can be very effective at certain jobs and can be great fun to be with.
Mania
- Has the same features as hypomania but taken to an extreme
- Additional symptoms, such as delusions of grandeur, overconfidence, impulsivity, and distractibility.
- Mania usually involves psychosis (a loss of touch with reality).
- When mania is fullblown, the person often exhibits unbridled enthusiasm with an outflow of incessant chatter that hurtles from topic to topic. No task is too difficult. No goal is unattainable.
- Results in series of disaster
Bipolar disorder type 2
Those persons who only experience bouts of depression and hypomania
Bipolar disorder type 1
Those persons who experience bouts of depression, hypomania and mania
Mixed state
Displaying symptoms of both severe depression (e.g., suicidal ideation) and mania (e.g., delusions of grandeur)
Rapid cycling bipolar disorders
Involving 4 or more mood episodes per year
Causal factors bipolar disorder
- Highly heritable –> twin studies estimate 80–90 percent heritability
- Many different genes in bipolar disorders –> genes that code for particular calcium channels and for particular proteins found at the nodes of Ranvier
Mood stabilizers
- Drugs that effectively treat depression or mania without increasing the risk of mania or depression, respectively. –> important because not treating causes severe and more frequent
- Mechanism by which mood stabilizers work is still a matter of debate, but for some reason many mood stabilizers are also effective in the treatment of both epilepsy and schizophrenia.
- Produce an array of adverse side effects (e.g., weight gain, tremor, blurred vision, dizziness) which encourage non-adherence to these medications.
Lithium
A simple metallic ion, was the first drug found to act as a mood stabilizer.
Describe the brain differences associated with bipolar disorders.
- Consistent overall reductions in gray matter volume have been reported
- In addition, there have been reports of several specific brain structures being smaller in patients with bipolar disorders, including the medial prefrontal cortex, the left anterior cingulate, the left superior temporal gyrus, certain prefrontal regions, and the hippocampus.
- Meta-analyses of fMRI studies of patients with bipolar disorders have found atypical activation in the frontal cortex, medial temporal lobe structures, and basal ganglia, as well as atypical functional connectivity between some of these structures, in a variety of cognitive states.
Describe some of the theories of the etiology of bipolar disorders.
- Evidence of hypothalamic–pituitary–adrenal (HPA) axis dysregulation ;
- Marked disruptions in the circadian rhythms also in their non-bipolar relatives;
- Alterations to GABA, glutamate, and monoamine neuro transmission
- Evidence that BDNF levels are lower when depressed or manic.
