
Generally speaking, Stephen tends to be a very light sleeper. He suffers hypervigilance as an aspect of his ptsd – something that plagued him years before he ever met Jack Aubrey, though was certainly exacerbated as a result of his capture and torture that occured while working with the man. ( Through no fault of Jack’s – Stephen was made out as a spy, and in fact it was Jack who came to his rescue in the end. )
There are several elements that factor in when it comes to Stephen and sleeping. His position must be furthest from the entry points as possible and generally facing the door. On a ship he is not as vigilant – he holds faith in the command Jack holds as much as he does the respect the men have for him as a physician – but he still makes certain to arrange his cot in a manner that makes swift exit simpler and is facing the entry. Even in the case of his study, his desk is positioned so his back is to a wall (never a window ) and always angled to see the entry points fully.
Another thing to note about this is that whenever Stephen goes out anywhere, he positions himself strategically. At the symphony or a university lecture he positions himself nearest the aisle, whilst at a restaurant he would take a seat in a corner nearest the door and angled so that he could see who was coming in and out.
That all said, generally speaking Stephen does not sleep well alone. Though nightmares do not plague him every time he closes his eyes, it is the fact that he cannot predict them that causes his anxiety toward the habit to rise. Especially after his torture, as he gained nightmares of confinement that sometimes are shiftless – there is no real event happening in the dream, only sensation – the feeling of being tied down and unable to move, and a pervasive sense of terror that borders on the primal.
To combat this situation, Stephen works and keeps his mind busy. He has an abundant love and dependence upon coffee, but eventually the body will make its demands known. If he truly feels he cannot sleep safely, he will find a means to conveniently fall asleep in Jack’s cabin, or seated among the lieutenants. The surrounding comforts of others, and the awareness that they will be vigilant while he cannot, assists him in achieving a relatively peaceful reprieve more often than not.
However, he does not like to misuse these methods often, lest he draw attention to his issues. So he will find other, stranger places to sleep – ranging from as simple as his own desk to as unusual as propped against the balustrade somewhere, citing sun and work as his reasons behind it. He’s also known to pass out on beaches, but that genuinely is the sun – and dehydration to boot!
The best sleeps Stephen ever obtains are the ones in which someone is sleeping beside him. For this reason, he does have a habit of pursuing romantic engagements on occasion if only to have the excuse to keep someone close for a week or more ( as long as he can manage, really )for literally no other reason than the desperate need to rest properly.
He is aware this self serving management technique is unfair to those who share his bed, and does generally attempt to be both a giving partner to make up for it, and perhaps a bit too quick to offer commitment to assuage his own guilt ( thus, generally, running people off unintentionally and thrusting him back into his cycles. )
NOTE: For those familiar with the Aubrey-Maturin books, please understand I operate on a film basis primarily and have taken hints from the books only. The canonical addictions Stephen uses to self medicate have been eradicated. For more information, please see the important notices on addiction, and this post for Stephen’s canon in particular.