The Biochemical Approach

The biochemical approach states that biochemical processes play a causal role in depression, and research has linked these disorders to chemical imbalances in serotonin and noradrenaline.

Schildkraut (1965) argued that too much noradrenalin in certain areas of the brain causes mania, whereas too little causes depression. Later research suggests that the same is true of serotonin.

Data that supports this is from research on non-humans given drugs that diminish noradrenaline production, they become inactive and sluggish- two symptoms of depression. (Wender and Klein 1981.) Similarly, when humans are given reserpine, used to treat high blood pressure there are increased brain levels of noradrenaline and/or serotonin. (Lemonick 1997.) Iproniazid (used to treat TB) produces elation and euphoria, and increases noradrenalin and serotonin levels.

Lithium Carbonate decreases noradrenalin and serotonin levels. Research indicates that the urine of depressed people contains lower than normal levels of compounds produced when noradrenaline and serotonin are broken down by enzymes. (Teuting et al 1981) this suggests lower than normal activity of noradrenaline and serotonin- producing neurones in the brain.

Abnormally high levels of noradrenaline compounds have been found in the urine of manic people. (Kety 1975) and the level of these compounds fluctuates in people with bipolar disorder. (Bunney et al 1972.)