Depression: Neurotransmitters Flashcards
AO1
Depression is caused by an imbalence of NT in the brain effects signals (D+S pathways)
Low S (receptors/sensativity) linked to low mood/high anxiety (S is calming hormone)
May be too much reuptake of S which lowers levels
S influences monoines like D (reward) and noradrenaline (alertness/energy/concentration)
Low S lowers D+N
Low D results in symptoms (anhedonia+lack of enjoyment)
Low N results in lack of energy/changes in sleep
High levels of enzyme monoamine oxidase linked (breaks down monoamines)
Faulty 5HTT gene causing less S when under pressure/stress
+AO3
Objective+empirical
Antidepressants increase monoamine alleviate depression showing reduced monoamine are possible cause
+Drevets et al (1999)
Found reduced S receptor-binding potential in u medicated depressed patients
+Versiani et al (1999)
Found that patients who had noradrenaline reuptake inhibitors increased their mood of changing bio can reduce symptoms (may be bio cause)
+Krishan & Nestler (2008)
Reviewed studies involving scanning cadavers, animals studies, PET scans etc. Point towards the monoamine hypothesis
+Rosen et al (1981)
Compared substances found in urine of depressed patients + control group. Compounds products as a by-product of the action of enzymes acting norepinephrine + S were present in larger amounts in depressed patients urine
-AO3
Most evidence for abnormal levels of chemicals in the brain is correlational (cause and effect)
Alternative theories
Reductionist (doesn’t include cognitive)
Difficult to measure chemicals in the brain (may come from other parts of the body-lowers V)
Treatment aetiology
Drugs don’t work for everyone m?
-Delgado (2000)
Found monoamine depletion did not make symptoms worse in depressed patients not taking medication
-Angoa-Perez (2014)
Found that mice without the gene for tryptophan did not show signs of depression
