An animal model of genetic vulnerability to behavioral disinhibition and responsiveness to reward-related cues: implications for addiction.

Rats selectively bred based on high or low reactivity to a novel environment were characterized for other behavioral and neurobiological traits thought to be relevant to addiction vulnerability. The two lines of animals, which differ in their propensity to self-administer drugs, also differ in the value they attribute to cues associated with reward, in impulsive behavior, and in their dopamine system. When a cue was paired with food or cocaine reward bred high-responder rats (bHRs) learned to approach the cue, whereas bred low-responder rats (bLRs) learned to approach the location of food delivery, suggesting that bHRs but not bLRs attributed incentive value to the cue.

The "delayed onset" of antipsychotic action--an idea whose time has come and gone.

For years, it has been known that the "onset" of the antipsychotic response is "delayed," and this notion is expressed in many major textbooks, informs clinical decisions and has even led to the search for biological markers responsible for this delayed onset. But is the onset of antipsychotic action really delayed? In this review, we bring together data from several recent studies of antipsychotic drugs that show that the onset of the antipsychotic effect is within the first day; the effect is distinguishable from behavioural sedation; is specific to antipsychotic drugs; is seen with oral and parenteral preparations; and is seen with typical and atypical antipsychotics. More anti- "psychotic" improvement is seen within the first 2 weeks than in any other 2-week period thereafter, and more improvement is seen in the first month than in the rest of the year of follow-up.