Why is the world vivid in mania, but bleak in depression?

Down in a hole
Image by ParanoidMonk via Flickr

No, I am not speaking metaphorically. Quite literally,there has been accumulating evidence that sense are sharpened and have great acuity in mania while they are dulled in depression and the effects can be seen within the same individual over time as he/she suffers from manic/depressive episodes.

The latest study to add to this literature is by Bubl et al that found that depressive people’s brain registered lesser contrast than that registered by normal control brains when presented with same black and white images. They used pattern electroretinogram (PERG) to find whether the contrast gains registered by depressive retinas (those suffering from MDD) were different from those of controls and they found a strong and significant association with the severity of the depression.

I have covered earlier studies that found that sense of taste was compromised in depression (and enhanced in mania) and similarly that the sense of smell showed similar effects. Some snippets from the earlier posts:

What this means is that if you increase the amount of serotonin in the brain, then the capacity to detect sweet and bitter tastes is increased; if you increase noradrenaline levels those of detecting salty and bitter tastes is augmented; while a general increase in anxiety leads to better bitter taste detection. This also means that an anxiety state produces more bitter taste perception whereas a depressive state (characterized by low serotonin) is marked by bland sense of taste with marked inability to detect sweet and bitter tastes. A stressed state , marked by abundance of noradrenaline, would however lead to more salty and bitter taste perception.


In one of my earlier post on depression, I had commented on the fact that those suffering from depression have less sensitivity to sweet and bitter tastes and as such may compensate by eating more sugar thus leading to the well documented diabetes – depression linkage.

In a new study it has just been discovered that not only depressives have bland sense of taste, their sense of smell is also diminished and they may make compensations by using greater amounts of perfume. Overall it seems that those suffering from depression will have bland subjective experience of flavor(which is a combination of both smell and taste) and thus may even not really find what they eat to be tasty.

Further on, I speculate prophetically that blander vision will also be found:

To me, this is an important finding. To my knowledge no research has been done in other sense modalities (like vision), but there is every reason to think that we may discover a bland sense of vision in depression. Why do I surmise so? this is because there is extensive literature available regarding the manic state and how things seem ‘vivid’ during that state including visual vividness. If depression is the converse of Mania, it follows that a corresponding blandness of vision should also be observed in those who are clinically depressed.

We also know that in extreme or psychotic forms of Mania, auditory hallucinations may arise. I am not suggesting that hallucinations are equal to vividness, but I would definitely love to see studies determining whether the auditory sense is heightened in Mania (maybe more absolute pitch perception in Mania) and a corresponding loss of auditory absolute pitch perception in depression. If so found, it may happen that music literally becomes subdued for people with depression and they sort of do not hear the music present in everyday life!

Whether other sense like touch, vestibular/ kinesthetic , proprioception (a heightened sense of which may give rise to eerie out-pf-body experiences in Mania) are also diminished in depression is another area where research may be fruitful.

Of course I have also speculated about the others senses and would love to hear studies supporting/contradicting this thesis. But given that senses are attenuated in depression and exaggerated in mania the question remains why? Which brings me to the topic of this post- why is the world bleak /bland to a depressive and vivid for a manic?

This was also the question asked by Mark Changizi (@Mark_Changizi) on twitter with respect to this new study uncovered today and I replied that this may be due to broaden-and-build theory being applied to sensory domain or sensory gating phenomenon differentially acting in manic/ depressive states, while Mark was of the opinion that it might be the result of physiological arousal with arousal being the variable of interest controlling whether the sense remain acute or dull?

I do not see the two views necessarily contradictory and it may be that chronic affect per se activates arousal and that is the mediating variable involved in its effect on senses; and we can design experiments to resolve this by measuring the effect of state sadness/ happiness/arousal on visual acuity (if the effects of state manipulations are big enough); howsoever, I woudl like to elaborate on my broaden and build theory.

In the cognitive, psychological and psychosocial domains the broaden and build theory of positive affect is more or less clearly elaborated and delineated. I wish to extend this to the sensory domain. I propose that chronic positive affect signals to our bodies/brains that we can afford to make our attention more diffuse, let senses be perceived more vividly as we have more resources available to process incoming data; conversely in a chronic low affect state we might like to conserve resources by narrowing focus/ literally narrowing the range of sensory inputs/reducing the sensitivity of sense organs and pool those resources elsewhere.

I know this is just a hypothesis , but I am pretty convinced and would love to hear the results of experiments anyone conducts around this theory.
Bubl, E., Kern, E., Ebert, D., Bach, M., & Tebartz van Elst, L. (2010). Seeing Gray When Feeling Blue? Depression Can Be Measured in the Eye of the Diseased Biological Psychiatry, 68 (2), 205-208 DOI: 10.1016/j.biopsych.2010.02.009

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  9. Adam G

    In Buddhist concentration meditation (involving well-practiced, very strong executive control over attention), there are levels of meditative depth called “jhana.” Each jhana is a step farther away from normative DMN-driven consciousness. (The DMN is brought under voluntary control in the first jhana. It is strongly inhibited in the 2nd jhana and all subsequent jhanas.)

    What does this have to do with mania? Simple. The 4th jhana leads to the experience of drastic awakeness and sensory clarity. (Unless the meditator has been taught to dissociate from external stimuli.) Sounds like mania, right? Yet there is a complete absence of hedonic tone. No sensations are experienced as pleasant, nor as unpleasant. All sensations are simply “present” and additionally “interesting” (i.e. SALIENT).

    I hypothesize that the experience of striking clarity and vividness (whether in mania or in meditation) is caused by increased salience attribution to sensory stimuli.
    (If asked how this happens, I would suggest the noradrenergic system as a likely candidate. Pro-noradrenergic drugs like pseudoephedrine and yohimbine cause the same vividness and arousal as the 4th jhana. Anti-noradrenergic drugs like clonidine cause the sensory dulling associated with depression.)

    This hypothesis is testable: Do manic individuals and experienced meditators performing the 4th jhana demonstrate increased coherence between the salience-processing networks and the somatosensory networks relative to controls, and do non-anxious depressed individuals experience decreased coherence? (Or, alternatively, do manic individuals show globally increased activity in salience networks, and atypically/bipolar depressed individuals, globally decreased activity?)

    One final hypothesis: maybe the salience angle is a red herring. Maybe increased salience is more an effect of increased arousal, rather than a cause of it.

    Personal use of aniracetam reveals that it also increases vividness like jhana and noradrenergic drugs. Aniracetam is an AMPA receptor positive allosteric modulator. It also yields metabolites that activate the cholinergic ascending Reticular Activating System. Thus, it probably doesn’t have any effects specific to salience processing, unlike the meditation procedures. It simply increases neurological arousal. We could test this hypothesis too… but I’ve spent too much time writing this comment, when I’m supposed to be writing on operant conditioning! So you figure out how to test that last one 😉

    1. sandygautam Post author

      Hi Adam,

      you make some very interesting points. It has always been my contention that salience attributed to events/ stimuli is heightened in mania and subdued in depression resulting in changes in vividness and sensory clarity; so we are more or less on teh same track. The link with noradreline looks promising and deserves careful scrutiny.

      Thanks a lot for taking time out and commenting and best of lunch with your operant research.

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