pair brain function and cognition. Numerous neurological and other medical condi-
tions may produce rapid onset of signs and symptoms mimi cking those of withdrawals.
Paradoxically, drug intoxications also must be ruled out, because, for example, lethargy
may indicate withdrawal from one drug  or intoxication with another drug.
Comorbidity
As with all substance-related disorders, adolescent conduct disorder, adult antisocial per-
sonality disorder, and other substance use disorders likely co-occur with other (or un-
known) substance withdrawal.
Other (or Unknown) 
Substance–Induced Disorders
Because the category of other or unknown subs tances is inherently ill-defined, the extent
and range of induced disorders are uncertain. Nevertheless, othe r (or unknown) sub-
stance–induced disorders are possible and are described in other chapters of the manual
with disorders with which they share phenomenology (see the substance/medication-
induced mental disorders in these chapters): other (or unknown) substance–induced psy-
chotic disorder (“Schizophren ia Spectrum and Other Psychotic Disorders”); other (or un-
known substance–induced bipolar disorder (“ Bipolar and Related Disorders”); other (or
unknown) substance–induced depressive diso rder (“Depressive Disorders”); other (or
unknown) substance–induced anxiety disorders (“Anxiety Disorders”); other (or un-
known) substance–induced obsessive-compu lsive disorder (“Obsessive-Compulsive and
Related Disorders”); other (or unknown) substance–indu ced sleep disorder (“Sleep-Wake