So, let's look at Sloth. This is more than simply laziness, but a whole family of behaviors that all have one thing in common: dependency on others.
Yes, Lust is also a type of dependent relationship, but Sloth is more personalized in a way that Lust is not: for example, some forms of Lust involve pornography or inanimate objects. Sloth may involve certain delusions like this, but the real core of it is the necessity of others to meet the needs of the slothful person.
The slothful person is too lazy to clean, but usually has any of a number of people who will provide cleaning or clean things when necessary. The hoarder becomes slothful in refusing to make decisions about what to dispose of, until relatives come and 'force' a clean-up, or a safer place to live, or something that keeps the hoarder unscathed by his behavior.
Sloth is a type of passive manipulation, because the lack of action to fulfill what is proper tempts others to step in out of a sense of duty, guilt, or concern. The slothful person knows that others will step in, and so he is free to carry on according to his passion rather than according to what is necessary and proper.
This is different from clinical depression, which is chemical in nature and unavoidable. Sloth can be escaped when the person senses danger, something that does not happen with true depression. Sloth is calculated in a way true depression is not.
This is not to say that all forms of 'depression' are not related to Sloth. Some people who are 'depressed' are really engaging in behaviors designed to elicit sympathy from others. So, the neglect and sorrowful affect are part of a show. This is 'emotional sloth,' where a person refuses to veil his negative emotions the way people usually do so as not to impose on others.
The emotionally slothful person can be the 'drama queen' who relies on the patience and charity of others while she acts out without regard for consequences. Whereas the lustful person schemes as to how to get emotions or behaviors out of people, the slothful person does not care, but passively relies on the sense of decency in others to keep the situation in control.
Sloth is permanent immaturity. There will always be a 'mom' and 'dad' to clean up after you.
A further refinement of this passion is akedia or acedia (http://en.wikipedia.org/wiki/Acedia). This sense of both irritable discontent and inability to focus is often associated with monastics, but is fairly common among ordinary folk. Akedia is a type of dissatisfaction with the world, which drives the sufferer away from constructive activities and eventually makes him a parasite within his community.
Akedia involves a great deal of Pride, since the discontent it harbors comes from the person's willingness to judge others and think himself superior. Again, there is also a certain degree of Lust as well, because the sufferer will invariably manipulate others to afford himself more comfort from his suffering, but in the end he will turn on those whom he has manipulated and will impose his negativity on them. He will expect them to support him.
Sloth is very common these days because we are in an era where people generally see themselves as consumers, either of commercial or governmental services. We no longer have a sense of being responsible for producing anything, but our production is tied strictly to our ability to gain things. Someone else will have to clean up the mess and pay the bills. There is no appreciation for our own work.
Sloth tells us that there is no need for self-improvement, because it is too difficult and really unnecessary if one can find an easier way of getting what one wants. So, Sloth sets in when the person chooses to forget honor. Here, we have another manifestation of Pride: "I'm too good to care what you think about me."
This is behind that casualness of modern culture. For example, the young man who goes to a job interview in a 'hoodie' is demonstrating his Sloth by telling the interviewer that the job is not that important, and since 'you really need me, you'll have to hire me anyway whether I wear this or a suit.'
After all, not having to care is a luxury. Sloth demands luxury without labor or merit. When one does not receive it, then the 'pity party' begins and the real sloppiness takes over.