Mental disorders are often draining. Fatigue, exhaustion, difficulty concentrating, poor memory, etc., are all a result of mental disorders. A lack of motivation can either be primary, expressed as a lack of interest in things, withdrawal or diminished activity, or secondary, as a consequence of other symptoms of psychosis.
Sometimes we underrate this or even forget it. What we need to remember is that we are not talking about laziness or unwillingness. Most of the reason is a bottomless feeling of hopelessness, exhaustion, anxiety and a kind of paralysis of the ability to think clearly. This means that all too often the person in question withdraws from family, friends or co-workers. They can become apathetic, spending all day in front of the TV or with computer games. Everyday things like getting up in the morning or washing up seem impossible.
(Some days simply washing up feels to him like an impossible challenge … as if he is being asked to jump over a wide crevasse in a glacier)
This is often a source of irritation and a strain on others. When we encourage someone to get up and do something, it is important to remember that the behaviour is due the illness and not laziness or lack of initiative.