The Collaborative International Dictionary of English v.0.48:

Demented \De*ment"ed\, a. [From Dement.]
   Insane; mad; of unsound mind. -- De*ment"ed*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

demented
    adj 1: affected with madness or insanity; "a man who had gone
           mad" [syn: brainsick, crazy, demented, disturbed,
           mad, sick, unbalanced, unhinged]

The Free On-line Dictionary of Computing (19 January 2023):

demented

   Yet another term of disgust used to describe a program.  The
   connotation in this case is that the program works as
   designed, but the design is bad.  Said, for example, of a
   program that generates large numbers of meaningless error
   messages, implying that it is on the brink of imminent
   collapse.

   [Jargon File]

   (1994-12-07)


The Jargon File (version 4.4.7, 29 Dec 2003):

demented
 adj.

    Yet another term of disgust used to describe a malfunctioning program. The
    connotation in this case is that the program works as designed, but the
    design is bad. Said, for example, of a program that generates large numbers
    of meaningless error messages, implying that it is on the brink of imminent
    collapse. Compare wonky, brain-damaged, bozotic.