There is plenty of information online about dealing with various behaviour problems, I'm going to add my own ideas now.
Separation Anxiety is one of the most common behavioural 'issues' expressed within the domestic dog. But Why? This goes back to their deliberate and selected breeding to work with us, to enjoy our company and treat us almost as one of their own. Some recent novel experiments using fMRI scanners have begun to show the extent of this with exploring emotion in dogs and recognition of various sounds including the human voice (http://healthypets.mercola.com/sites/healthypets/archive/2014/06/06/dog-human-brain-response.aspx?x_cid=20140606_lead_facebookpets) . The fact dogs respond to these is unique in the animal kingdom except for with humans, we are also capable of recognising the difference between dogs vocalisations, even if we do not live with dogs (http://www.wired.com/2011/06/dog-bark-origins/). This mutual understanding has developed over thousands of years of cohabiting.
So if dogs have been bred to understand and want to be with people, it is safe to assume that separation anxiety is perfectly justified. With the neotinization of dogs to stay in a continued 'puppy-like' state, we can expect them to feel more comfortable and at ease in our presence. So how can we combat that sense of loneliness when a dog is well.. alone?
As with most socialisation and adjusting to human life, there is a lot of desensitisation going on when dealing with separation anxiety. The idea is to get a dog who is not anxious and can in fact be happy with his or her own company. This usually starts from puppy hood, though due to the start many dogs get, this necessary training is often left out and a large proportion of rescue dogs will have separation anxiety to some degree and can be made worse if over-attachment is allowed in the initial introductory stages. So one of the key things we need to remember is ' giving the dog the confidence to be left alone'.
So what are the basics in teaching a dog to be happy when left alone? Well we make it a positive and safe experience for them. This means while you are gone you want things to occupy your dog, toys, safe chewy things such as a nylabone or stuffed kong or a buster cube filled with treats that the dog has to work for. I do not recommend rawhide treats unsupervised, as dogs can swallow them in large chunks which can block the gut. Not good. If you have a dog with known separation anxiety, some things they can chew without you being too worried about it, such as old boxes with any tape or staples removed. Old blankets from a charity shop are great while your dog learns to be alone as they are cheap and it matters less if they get chewed or ripped. I do not recommend soft beds as these can get pulled apart, fluff everywhere which can get eaten by explorative puppies. Ideally introducing a large crate in which the dog can stand, lie down and move around with ease is ideal, though they should not be confined to one all day as this is unfair. Crate training would need to be introduced as well. If you have a dog that gets easily disturbed by noises outside, putting on the TV or radio is ideal. Classical music is best as it has been shown to have a calming effect on the dog (http://blogs.discovery.com/daily_treat/2012/11/can-classical-music-calm-stressed-dogs-study-says-yes.html). This would need to be loud enough to dull noises from outside which can stress the dog, but obviously not loud enough to disturb any neighbours. And lastly slowly introducing your dog to being left for longer periods of time. Even a puppy can be left for 10 mins and have this slowly increased as long as it is in a safe environment. With some dogs showing extreme anxiety, just removing yourself from the room for a few seconds then returning while the dog is calm and then slowly increasing this to a few minutes etc will help. Remember to always make the experience of being alone a good one.
Its also worth noting that over-attachment often coincides with separation anxiety, and teaching your dog to be away from you when you are in the house, such as lying quietly on their bed with a toy or chew, not being allowed to follow you from room to room can be a good way to improve confidence and help prevent the symptoms either worsening or even becoming present. It is important to remember that a dog should not be left more than 4 hours on their own, 6 at a push if you have an older dog who does not become anxious, though having someone to check in on the dog is a good idea. If you work it is a good idea to employ a dog walker or sitter who can come in regularly and interact with your dog, either in play,just keeping him company or taking her for a nice walk to break up her day. There are also various services where you can drop your dog off with a professional dog sitter while you work meaning they rarely have to be alone. There is the option of kennels also. So those are some basic bits of advice. Hopefully they may help in some way if this is a problem. Have fun with your dog!
Dog Trainer, animal lover, artist and photographer