If 'sick role' requires the patient to take on the roles which are expected by the society from the sick individual, how the psychotic's detachment from reality can be ever translated into the morality of sickness?
It is tempting for a person disabled by psychosis to become very dependent (adopt the sick role) and very difficult to lift oneself out of that lethargic state and make the most of one's life. This is, of course, not true for everyone. Some people with psychosis rebel against the idea of being seen as "sick," and you have to admire that - except that it often gets you into further trouble.
Dear Ashkan, as you will be aware there any many contributing factors to the development of the 'sick role'. The theory by Parson's has been around a long while and the societal and political landscape has changed a lot since then. There is a continued need for further research around the negative and affective symptoms associated with psychosis, which may be construed as the 'sick role'. However one issue that is sure to force people with psychosis into any form of 'sick role' is when they are referred to as the illness or diagnosis they have been given, thus restricting recovery and belief of a better future - referring to "the psychotic" would be a prime example. There is no "them & us". We should be working towards breaking barriers to recovery such as stigmatisation and labelling, after all "them ARE us".
Ashkan - you ask good questions for which there is probably no clear answer. Certainly, many, if not most, symptoms of psychosis are not voluntarily chosen. One of those symptoms is, by definition, an "avolitional" state. But, on the other hand, there is some comfort in knowing that nothing is expected, that one needn't get up early, needn't get dressed, needn't cook or clean or move much. It's tempting to some people to bask in the inertia of knowing that most of one's immediate needs will be looked after by others. That is true no matter what the illness is. Chronic illnesses do that to people.