SAD

This time for the Weekly Blog Post, it's the turn of our PsychSoc President, Olivia.

A man at my boyfriend’s office got a SAD lamp for his desk last week... ?? I hear you cry. Well, did you ever read that Philip Pullman book, where the kid has a knife that can cut a window in the air into a parallel dimension? Well, that’s kind of what these lamps look like. A glowy rectangle to another world.

SAD lamps were developed to treat Seasonal Affective Disorder (SAD). A depressive illness with one of the most unfortunate acronyms going. It's particularly unfair as SAD is actually pretty bleak and debilitating, and substantial research has cemented it as a very real mental health condition.

So, what is SAD? SAD is having the same triad of symptoms seen in depression - persistent low mood, anhedonia and fatigue - but it's seasonal.

Here are the key diagnostic factors;

• diagnostic criteria for recurrent major depressive disorder are met

• > 2 year pattern of seasonally related changes in mood

• full remission of mood takes place at regular time of the year (typically spring/summer symptom remission)

How common is it? Well, maybe you’ve noticed a change over the last few weeks too? As we move into autumn, many will experience a lighter version of SAD, with subtle dips in mood and motivation. Or, perhaps your mood has taken a more obvious nosedive and things are feeling a lot more serious. Statistically, 23 (3%) of us at the med school have it! Either way, we’re almost definitely going to encounter SAD; if not on a personal level, then in our future patients. Afterall, BSMS’ major lines of doctor-production are GPs and Psychiatrists.

Why does it happen? As in depression, people with SAD are thought to have difficulty regulating serotonin, one of the neurotransmitters believed to be responsible for maintaining a level mood. One research group has shown that during winter, people with SAD express 5% more SERT; the protein that removes serotonin from the cleft via the presynaptic bouton (©HWitchel).

Doubling down on this, those with SAD may also have difficulty with overproduction of melatonin, a molecule that steadily increases in your blood over the day until it makes you feel sleepy by the evening. This supports the general feeling of lethargy felt by those with SAD throughout the autumn and winter months. Altered melatonin can in turn throw off your circadian rhythms, which sets into motion a cascade of problems, including cortisol (stress hormone) peaking with greater intensity, and at unhelpful times of the day.

Where’s The Convincing Graph? If you take away nothing else from this blog, then it should be this graph (shorturl.at/EKOW7). It’s not about SAD; it’s about bipolar. Specifically, it suggests that manic episodes happen far more frequently in the summer. And that depressed episodes crop up more often in the winter, with another small bump in the summer holidays. So why am I talking about bipolar? Well, firstly because it’s so good at highlighting the trends seen between seasons and altered moods on a biochemical level. And secondly, these same cyclical trends are seen in SAD, too, but the studies into bipolar are far more robust. Gotta get that P number <0.05.

But perhaps more interestingly, there is increasing evidence from other groups to suggest SAD and bipolar overlap as diagnoses. Adding weight to this cross-over, clinicians and research groups have reported that some patients with SAD experience hypomania during spring and summer.

Treatment As in depression, SSRIs have been seen to alleviate symptoms in some, particularly fluoxetine. However, as with depression, SSRIs are ineffective in many. There is a good amount of research into the effect of sunlight on those with SAD. Exposing participants to sunshine during the morning over a two week period in winter improves symptoms of depression, and it does so in a ‘dose’ dependant manner. Interestingly, research into those without SAD who work night shifts as their sole source of income also show benefit from exposure to ‘light treatment’.

And finally, SAD lamps. Do they work? I’ve had a look into some credible research papers, and it seems they can make a difference. So maybe my boyfriend’s colleague is onto something after all. But for now, let's save that electricity money for central heating and hit the South Downs at the weekends