Martin is an individual schizophrenic person who feels ambivalent about most issues. He has no goals and does not seem to have the energy or interest to think about them. He certainly cannot make decisions. These symptoms would markedly belong to in the diagnostic criteria.

The disturbance here is attributable to the physiologic effects of another medical condition. He is suffering from disturbance or loss in volition.

Explanation:

Schizophrenia is a mental disorder that disturbs someone's ability to think, it makes a person misjudge the realities of life. Volition is the factor of using your self ability, it involves having the will to make your own decisions.

In this case Martin is already known to be suffering from schizophrenia, which makes him ambivalent about most issues. We are also told Martin has no goals and he has no zeal to think about them. Which means that Martin lacks the ability to take decisions and responsibilities, in order words he lacks motivation. Thus, it is clear he is suffering from loss in volition.