Biology of mood disorders

Problems

Studies have found that 60% are fully or partially noncompliant after a major episode of illness (Keck et al., 1998)

Relapse rates have been found to be 3-times higher in those adolescents who discontinued lithium use than those who did not


Non-compliance reasons include: Missing high periods, objecting to having one’s moods controlled by medications, lack of information about the disorder and lack of social or familial support (Colom et al., 2000)

ECT

Short term relief – long-term benefits doubtful, and there are side effects

Primarily for treatment-resistant severe depression

Lasting memory loss
Frightening
Unclear mechanisms of effect
Benefits may be short term

Biological Explanation

Neurotransmitter models of mood disorders have focused on: Norepinephrine, Dopamine and Serotonin – very complex interactions
Dysregulations in these neurotransmitter systems interact with deficits in other neurotransmitter systems (e.g., GABA)


Mood disorders are generally associated with decreased sensitivity of the serotonin receptors (Stockmeier, 2003)

Many of the brain region deficits involved in BD are involved in “emotional reactivity and regulation” . . similar to those in unipolar depression (Davidson, Pizzagalli, & Nitschke, 2002)

The Amygdala: which is involved in the detection of the significance of emotionally salient stimuli

The Prefrontal Cortex, Nucleus Accumbens, Anterior Cingulate and Hippocampus: Areas involved in the effective “Cognitive Regulation” of emotions, reward-sensitivity and goal pursuit

Treatments

Types of drug

Selective serotonin reuptake inhibitor (SSRI)

Monoamine oxidase inhibitors (MAOIs)

Dry mouth
Nausea, diarrhea or constipation
Headache
Drowsiness
Insomnia
Dizziness or lightheadedness
Skin reaction at the patch site

SSRIs. block the reabsorption (reuptake) of serotonin in the brain, making more serotonin available.

Drowsiness
Nausea
Dry mouth
Insomnia
Diarrhea
Nervousness, agitation or restlessness
Dizziness
Sexual problems
Headache
Blurred vision

An enzyme called monoamine oxidase is involved in removing the neurotransmitters norepinephrine, serotonin and dopamine from the brain. MAOIs prevent this from happening