I knew a girl who would do this and it was a big part of her Bipolar illness. She would have manic episodes where she would think she could go all of these jobs, and would apply for a whole bunch of them, and by the time she had gone through the interview processes and everything else that happens prior to getting hired, she would have cycled into a depressive episode. She'd turn down the job offers, neglect to return phone calls, or show up to the job a couple of times before finding herself unable to do it.

I would really advise you to find a sliding scale therapist (if you cannot afford one or don't have private/public insurance) and discuss these issues with them. Getting a job actually would be beneficial for this, because you might get health insurance coverage with a job, and then you could seek better care for your mental illness. I think a lot of times people say they "don't care" about things when really they are afraid and don't want to admit it.

Maybe you could try making a list of the job offers you have gotten. Then write down the reasons you applied for those jobs in the first place - what made you think you wanted those jobs? And then write down the reasons you decided not to accept the positions. I think that would be a really interesting list to look at and could help you figure out if you are just applying for jobs you don't really actually want, if you are afraid of something about the jobs you are getting offered, or if there is something else going on, why you are choosing not to accept the jobs.

Let us know if your situation improves and good luck.