While our knowledge of the working brain is still limited, in most instances of clinical depression it is likely that neurotransmitter function is disrupted. Another term for neurotransmission is ‘nerve conduction’, but what does this mean?
The human brain contains about 100 billion neurones, or nerve cells, which are a bit like tiny wires. Wires in a TV are joined together by solder, but the brain’s wires are joined by junctions called ‘synapses’. A signal from one part of the brain to another travels as a series of electrical impulses along a neurone until it reaches a synapse. At that point the synapse releases a tiny speck of a chemical, a ‘neurotransmitter’, which jumps the gap in the synapse and lands on the surface of the next neurone, so passing on information from nerve cell to nerve cell. In normal brain function, the signal is as strong in the second and subsequent neurones as it was in the first.
There are thought to be many different neurotransmitters in the brain for many different purposes, one of which is undoubtedly mood regulation. So far, about 100 have been identified, including serotonin. Serotonin is known to be involved in three important circuits: sleep, mood and aggression, and pain control. It is likely that in most causes of depression (especially non-melancholic depression), serotonergic transmission in the brain is less active, and there is less serotonin available in the synapse to stimulate the flow of information from neurone to neurone. Lowered levels of serotonin are associated with depression and suicidal behaviour, as well as with impulsive and aggressive behaviours.
It is likely that in melancholic and psychotic depression other neurotransmitters such as noradrenaline and dopamine fail to function normally across differing regions of the brain.
It is clear, therefore, that the extent to which different neurotransmitters and varying circuits are involved contributes to the principal sub-types of depression. This has ramifications for the effectiveness of the various classes of antidepressant drugs and other physical treatments such as electroconvulsive therapy, transcranial magnetic stimulation and mood stabilisers.
✰ What’s the solution?
Causes and triggers of depression can operate at different levels. These are:
- biological (for example, genetic, the effects of drugs and/or specific medical problems);
- psychological (for example, low self-esteem, personality style); and
- social (for example, distressing life events, dysfunctional relationship).
Solutions, too, can be considered at biological, psychological and social levels.
Any biological treatment must involve the correct identification of the principal depressive sub-type. For psychotic and melancholic depression, the primary treatment solution is generally physical (such as antidepressant drugs), whereas for many of the non-melancholic disorders the primary treatment is more likely to be psychosocial.
Treatments, however, are not always linked to causes. One wise psychiatrist noted that ‘migraine is not caused by an insufficiency of aspirin’. A significant percentage of the non-melancholic depressive disorders respond to antidepressant medications, and, while a patient with a melancholic depression may respond well to an antidepressant drug, secondary issues might be best dealt with using an alternative approach (for example, counselling for marital problems).
A pluralistic or integrated approach may also be of benefit.
Assuming that an individual’s depression is being maintained by low levels of serotonin in the brain, then alternative therapies (not all conclusively proved to date) might involve some of the suggestions listed below.
Imagine all the synapses as leaky rain tanks running low on serotonin. The obvious solution is to find a way of refilling the tanks. This could be done by turning off the tap or by mending the leak.
Turning off the tap. This means, stop doing anything that is contributing to the problem. For example:
- address the trigger that caused the problem;
- sleep where you are unlikely to be disturbed;
- check whether any medication you are on can cause depression;
- get any thyroid or other medical problem treated;
- avoid caffeine as it contributes to insomnia and anxiety;
- as far as possible avoid major life changes or dramas;
- avoid alcohol and illicit drugs;
- treat chronic pain;
- declare a truce in major conflicts; and
- don’t take up smoking.
Mending the leak. Stop the drain of serotonin and other neurotransmitters from the synapses by using an appropriate antidepressant medication. This may not only alleviate the depression but may also modify an ‘at-risk’ personality style (for example, ‘anxious worrying’ or ‘irritability’) thus increasing resistance to future depressive episodes.
Psychological treatments aim to support and counsel the individual during the depressive episode, as well as generate resistance to future episodes by increasing self-esteem and modifying at risk personality styles. Cognitive Behavioural Therapy (CBT) and Interpersonal Therapy (IPT) are the most common formalised approaches.
Social interventions aim to decrease the occurrence and impact of stressful events and promote the socialisation of the individual. The depressed person is encouraged to take part in pleasant activities, counteracting any tendency to shun social contact and thus maintain the depression. A shy individual may be encouraged to develop a repertoire of socialising strategies (through social skills training) or to use assertiveness training to become more self-assured. ‘Social engineering’ approaches are also relevant here; for example, encouraging someone in a dysfunctional relationship or work environment to make changes that will boost self-esteem.
(extracted from) Dealing with Depression: A Commonsense Approach to Mood Disorders by Gordon Parker, published by Allen & Unwin