What is the difference between sadness and depression?

Sadness or being sad is an emotion, and depression is a mood disorder. So, we have to think about what is the difference between an emotion, and a mood. 

An emotion is a short lived experience in our body that will have a physiological component, it will have a thinking component, and it will often have a behavioural component. But they tend not to last very long, and our emotions will be contingent on the environment. Something scary happens, you feel frightened, something dreadful happens - you feel sad. So, we respond to that. But typically, the emotion then passes. 

Whereas for a mood, what we're looking at is an enduring experience of something affective, referring to the emotional component, but it is something that's lasting much longer. So, straight away, we're looking at depression as something that's lasting longer than sadness. When we think about depression, we're really talking about a clinical diagnosis for someone who is experiencing these enduring feelings of sadness, that will be accompanied by a host of other experiences, or symptoms. So, that might look like changes in their sleeping habits, changing in their dietary habits, there could be thoughts of self harm or suicidality, there'll be a sense of helplessness, and reduced mood or apathy.

I think for diagnosis, you have to have had these experiences for at least two weeks, and they have to be impacting on your ability to function in the world. They have to be distressing to you, and they have to be what we would call - deviant from the norm, which just means that you're having an experience that's not part of most people's everyday experience.

Whereas sadness is not like that. Sadness is in fact part of the everyday experience. We all have it when something upsetting happens in life. We respond to the sadness, and the sadness emotion will shift as the environment shifts, and updates itself and we no longer need to be sad.

Why do we sometimes cry when we are happy?

So, built into this question is a sense of disbelief that we could possibly cry when happy, because probably tears have been associated culturally with being upset, or being sad. But, we have to ask the question, what is the function of crying? 

Research on various animals, as well as on humans, would suggest that crying is an emotional regulation strategy. So, when your nervous system gets overwhelmed with emotion, and reaches the peak experience of emotion - it somehow has to open the valve, and let off some steam, so that it can bring itself back down to what we would call - homeostasis. Which just refers to normal functioning balance in the nervous system, because the nervous system doesn't want to be too hot, or too cold for too long. 

So, if you are happy, perhaps what can happen then is the nervous system tries to bring you back down to a more balanced state, and it does that by letting off some of that emotional energy through tears.

How can a polygraph detect when we are lying?

The short answer to that is it cannot, because we've got multiple issues here. The first one to start with is what psychologists have called - operationalisation. Huge word, but basically what it means is how do you measure something. So, something like lying, we can define it as not telling the truth - but how do you know what the truth is, is the first question we have to ask ourselves. If you don't know what the truth is, then you don't know if someone's lying. It's a huge problem. 

So, when we think about operationalisation, we are asking to what extent we can design a measurement that is really, really accurate and really, really good at measuring the thing we're interested in. So in this situation, it's lying. But, we don't know what the truth is a lot of the time. So what we need to do is try to indirectly measure the thing that we're interested in. That's one way of operationalising lying, and you can do that with something called a polygraph. 

A polygraph will measure your physiological responses when speaking about something. The idea being that lying is correlated with, and is associated with bodily experiences of perhaps increased heart rate, or respiration, or getting warmer. 

But, it is just an association. Not everyone who's lying will have that experience. So, the polygraph works, or is supposed to work on the assumption that if we lie, our body responds in a particular way, and we can pick that up. But of course you can see lots of pitfalls in that argument, because perhaps you're hot because you're in a hot room. Perhaps you are responding in a certain way because you've got a medical condition that makes you respond like that all of the time - regardless of whether you're telling the truth, or whether you're lying. 

So, really all the polygraph tests can do is tell us about the physiological response. The question is then can we interpret the physiological body response as an indirect measure of lying - and I don't think you can, at least not all the time.

What is ADHD?

Similar to other mental health conditions, there is a formalised definition of what ADHD is. There's a few things just to pull out from that, you can find the definition for yourself if you look up ADHD DSM-5, which is the Diagnostic and Statistical Manual of Mental Health Disorders.

But ADHD has got two components. We've got the attentional component and we've got a hyperactive component, and that's what makes up the name ADHD - which is Attentional Deficit Hyperactivity Disorder. What we're looking for then is a challenge in regulating attention. People often think about ADHD as when someone has no attention, but that's not true because they can have hyper fixations of attention on particular things.

So the question is not the lack of attention, but rather the regulation of attention - where does my attention go? And then we've got the hyperactivity part, which is more often seen in males who have a diagnosis of ADHD, and that refers to sort of impulsive behaviours and difficulty in regulating one's own movements.

What we think in ADHD is hyperactivity - what it's actually trying to do is to arouse the nervous system. So in ADHD, perhaps the brain itself is not aroused enough. So because it's not aroused enough, it's trying to make itself go back up to that level of functioning that it wants to have. It does this with the hyperactivity, because when you're hyperactive, you're sending a lot of signals to the brain, the brain says now I've got back up to that level of activity that I want to have. 

What's interesting is that ADHD looks different in different people. Some people might have more of an inattentive type, and other people might have more of a hyperactive type. This difference has to be accounted for because when it comes to diagnosing, looking, and assessing ADHD - it could look different. But, there are some commonalities that are important to consider in the definition. So typically what we're looking for in ADHD is that these difficulties with attention, and hyperactivity, have been there since childhood. Because what the clinician is trying to do is rule out any other disorders that may have happened in adulthood, that could have been caused by something else. 

So, we typically think of ADHD as a developmental experience that people have and so part of understanding what it is, is to look at how it develops in young people. If it maintains over the long term, then perhaps what we're looking at is something like ADHD. But if it's a spontaneous expression of difficulty in paying attention, or regulating yourself in terms of being hyperactive, that's happening suddenly in adulthood - then that sort of points to a different disorder which helps us to know what ADHD is, when we compare it to what it is not.

Why is there a minimum age for drinking alcohol?

So, research on adolescent development has shown us two important things. First one is that the brain is continuing to develop very quickly, all the way through your 20s into your 30s. The part of the brain that's taking a little bit longer to catch up, is the part of the brain that would be involved in our inhibitions, and stopping us from doing things that are perhaps not very good for us. That takes the longest to develop.

Ironically, the part of the brain that's developing very quickly is the part of the brain that likes taking risks, likes being rewarded, and doing fun things. So, with that knowledge of development, that's why there is a cutoff for drinking, because we need to respect the fact that when you start and you're having fun with alcohol - it's really difficult to stop at that age. 

The second thing that this research has shown us is that adolescents when taking risks, or young people when taking risks, are much more affected by the presence of their peers - so you can think about peer pressure, and peer influence - and they're much more affected by their peers. So, if we accept that with the development of the brains of young people, that the part that would stop them drinking too much is underdeveloped, and the part that wants to drink a lot is overdeveloped, and then you add in the fact that all of the teenage brains are the same way, and then you add the fact that they really influence each other at that age - you can end up with catastrophe.