@ladyjane - I can feel your frustrations about your husbands behavior and it must be equally frustrating because he refuses to seek medical attention for it.
I too suffer from low serotonin depression. The anti-depressants I was taking seem to only make things worse because of their addictive side effects.
I began a research on low serotonin causes and how to increase serotonin in the blood naturally. Here are a few things that have helped me balance my mood swings and get my life back.
First and foremost is to get plenty of natural sunlight. Next is the addition of Omega-three fatty acids like that in fish and fish oil supplements. St. John's Wort is another safe and effective home remedy I've used for fighting anxiety and depression. Vitamin B6 and 5-hydroxytryptophan or 5-HTP have also been helpful at boosting my bodies serotonin level.
There are many websites, books and articles on the subject to help guide you. Most all of them will offer the same suggestion to get more sunlight, drink less caffeine, no alcoholic beverages and to eat a healthy diet of fruits and vegetables.
All of these treatments are designed to increase the blood serotonin level naturally. I'm sure you'll find just the right one to beat your husbands low serotonin symptoms and can then start living a happier healthier life.