Individuals may experience physical manifestations of their loneliness, says John Cacioppo.

Question: What are the physiological effects of loneliness?

Cacioppo:    Among the physiological effects of loneliness that we and others have documented are increased vascular resistance, which is increased resistance of blood flow circulating throughout your body.  That increased vascular resistance we see not only when people confront stressers but even at baseline, when just sitting normally during the course of a day.  In one study, in fact, we put small, ambulatory devices on people and they walk around and [were beeped] and sat down and pressed some buttons and we were able to measure vascular resistance and blood pressure, and found in those individuals, during the course, the lonelier they were, the higher the vascular resistance, just as they walk around in their everyday life or sat in a chair during the course of a day.  Over time, vascular resistance in other studies [this has] been associated with the increased blood pressure.  We too find, both in cross sectional and longitudinal studies, that loneliness in middle age and older adults, when homeostatic mechanisms like blood pressure regulation start to degrade, loneliness is associated with higher levels of blood pressure.  We find, in the morning, stress hormones, cortisol in particular, rise.  When you’re sleeping, you don’t need a lot of the stress hormones to promote energy.  During the day, you do.  You see this big surge when you awaken.  Lonely individuals show larger increases in cortisol in the morning than non lonely individuals.  That’s been shown cross sectionally, what we did was to look longitudinally.  We took individuals and measured their loneliness in the evening and then measured the morning rise the next morning, and we found, even longitudinally, the lonelier they were the night before, the higher the morning rise in stress cortisol the next day, which was a very interesting result that suggested something about loneliness, not some other individual difference it’s contributing.  Cortisol is a very powerful hormone, and not only does it help metabolize fats and sugars to give you energy, but it also controls inflammation, and it operates on that at the intracellular level.  Cells and the immune system have receptors for cortisol, and those receptors, when cortisol strikes those receptors on these cells, sends a chemical signal to the nucleus of the cell.  In the nucleus of the cell, there’s other chemical signals being produced by the DNA called RNA transcripts that travel out to the surface of the cell and then control inflammation throughout the body.  What we found in collaboration with Steve Cole at UCLA was that the cortisol receptors were down regulated in lonely individuals.  This chemical signal from that receptor to the nucleus was muted somewhat.  That’s probably because of these higher levels of cortisol, these receptors adapt just like you do when you go outside in the bright sunshine, your eyes start to adapt.  You get used to that higher level.  So, the signaling is reduced.  Well, as a result of that reduced signaling of cortisol to the nucleus of the cell, the DNA to RNA transcription itself was impacted, so the signal of inflammation was less constrained, the cortisol is less… it’s less constrained and there was more inflammatory signaling coming out of the nucleus of the cell.  So that was an intracellular process.  Not too surprisingly, in light of that finding, loneliness has been associated with decreased immunity.  There’s other effects, such as loneliness being associated with faster progression of Alzheimer’s Disease, and loneliness, of course, is associated with poorer health outcomes. 

Question: Is loneliness recognized by the medical world?

Cacioppo:    Doctors have underestimated the importance of loneliness.  We have characterized individuals as rugged individualists.  We praised the solitary scientist or the noble athlete who spends, you know, time training and then excelling as an individual at their sport.  There’s nothing wrong with that, but it leads us sometimes to underestimate the importance of being connected.  We are fundamentally a social species.  Our capacity doesn’t derive from our individual mind.  Our capacity derives from our ability to work as a collective.  If you just look at any city or any society, you see that we have the capacity, we do as a species because we specialize work together.  We can trust one another.  Well, we couldn’t drive through the city streets if we couldn’t trust people would follow certain, follow certain conventions and norms.  So, we take it for granted because it’s so fundamental, the importance of connection, but that means that when doctors see individuals, they sometimes underestimate the root problem, that is people do feel disconnected from others, both the mental and the physical health problems that that can create.

Question: Can prescription drugs help fight loneliness?

Cacioppo:    The question of whether drugs are appropriate to combat loneliness is a difficult one.  What we do know is that many of the [cognitive] behavioral procedures available are sufficient for most individuals to deal with loneliness.  Much of it is we don’t know, we treat the signal as if it were a neuroticism, or a disease rather than what it is, and that is part of what it means to be human, it’s part of what it means to be connected.  It’s a signal, if we were sensitive to and we responded to…  You know, I’m feeling lonely so maybe I should stop just working and perhaps pay a little more attention to my family or to my friends, then that can go a long way toward in fact creating a better environment for all of us.  If you treated it simply with drugs, that may allow me to work in isolation more but that’s actually not something that’s positive or beneficial for a society as a whole, or for human species as a whole.  That doesn’t mean, however, that, for certain individuals, for short periods of time, that it might not be important to diminish the intense feelings of loneliness so that a person is able to regulate and deal more carefully with their problems.  One of the ironic effects of loneliness is it impairs executive functioning.  It impairs an ability to actually regulate one’s behavior.  And it makes sense.  You feel threatened.  You feel rotten. You feel miserable.  Life is stressful.  It makes it very easy to eat fatty foods.  It makes it very easy to not exercise.  In fact, we find loneliness to be associated with both kinds of poor health behaviors, and it’s because those are quick little rewards that help make up for the misery in which one is living.  If you diminish that feeling of loneliness or the pain of loneliness, it diminishes the depletion of executive function and that’s really critical to help one think more realistically about the interactions with other people.  So I can see kind of a need for phasic or for temporary medical interventions on some occasions, but one wouldn’t want to use it as a replacement.