1. Answer: E. According to the DSM-IV, there are five characteristic symptoms of schizophrenia including delusions, hallucinations, disorganized speech, disorganized or catatonic behavior, and negative symptoms (affective flattening, alogia, or avolition).

2. Answer: A. According to the DSM-IV, there should be continuous signs of disturbance persisting for at least 6 months. This 6-month period must include at least 1 month of characteristic symptoms (or less if successfully treated) and may include periods of prodromal or residual symptoms.

3. Answer: E. Schizophrenia, disorganized type, is not characterized by prominent delusions or hallucinations. Delusions and hallucinations, if present, are fragmentary and are not organized into a coherent theme. This type of schizophrenia has a continuous course with no significant remissions.

4. Answer: C. According to the DSM-IV, all of the choices are recognized features of schizophrenia, catatonic type, except disorganized behavior (which is a feature of Schizophrenia, disorganized type). The other feature of schizophrenia, catatonic type is peculiar voluntary movements such as posturing stereotyped movements, prominent mannerisms, or grimacing.

5. Answer: A. According to the DSM-IV, the duration criterion for the diagnosis of schizophreniform disorder is at least 1 month but less than 6 months (including prodromal, active, and residual phases). Brief psychotic disorder has a duration criterion of less than 1 month, and schizophrenia requires a duration criterion of at least 6 months.

6. Answer: B. Disorganized speech or behavior is a bad prognostic feature of schizophrenia.

7. Answer: B. According to the DSM-IV, to diagnose schizoaffective disorder, delusions or hallucinations must be present for at least 2 weeks (not 4 weeks) in the absence of prominent mood symptoms.

8. Answer: B. According to the DSM-IV, to diagnose delusional disorder, nonbizarre delusions must be present for at least 1 month (not 3 months). Delusional disorder has various subtypes including erotomanic type, grandiose type, jealous type, persecutory type, somatic type, mixed type, and unspecified type.

9. Answer: E. According to the DSM-IV, negative symptoms are not included in the diagnostic criteria for brief psychotic disorder. The duration criteria specify that one of the above four symptoms should last for least 1 day but less than 1 month, with eventual full return to premorbid function. It is further specified as with marked stressor, without marked stressor, and with postpartum onset.

10. Answer: A. According to the DSM-IV, to diagnose major depressive disorder, the subject should have at least five of the nine symptoms of depression over a 2-week period. At least one of the symptoms should be either depressed mood or loss of interest or pleasure in usual activities.

11. Answer: E. According to the DSM-IV, to diagnose major depressive disorder, the subject should have at least five of the nine symptoms of depression over a 2-week period. At least one of the symptoms should be either depressed mood or loss of interest or pleasure in usual activities. The other seven symptoms are significant weight loss or weight gain, insomnia or hypersomnia, psychomotor agitation or retardation, fatigue/loss of energy, worthlessness, diminished concentration, and suicide ideation. Decreased need to sleep is a symptom of hypomania or mania.

12. Answer: B. According to the DSM-IV, to diagnose major depressive disorder, the subject should have at least five of the nine symptoms of depression over a 2-week period. At least one of the symptoms should be either depressed mood or loss of interest or pleasure in usual activities. Significant change in weight is also one of the criteria. The DSM-IV specifies a change of more than 5% of body weight in a month (either weight gain or weight loss) as significant.

13. Answer: D. The symptoms of major depressive disorder and bereavement are very similar, and the fact that some of the subjects with bereavement develop major depressive disorder makes it even harder to distinguish the two conditions. In subjects with bereavement, however, the symptoms last for less than 2 months, and they do not experience marked functional impairment, worthlessness, suicide ideation, psychotic symptoms, or psychomotor retardation. Helplessness is a common symptom in bereavement.

14. Answer: D. An untreated episode of major depressive disorder typically lasts for 6 months or longer. In about 5% to 10% of individuals, the full criteria for a major depressive disorder continue to be met for 2 or more years, in which case it is considered as chronic. Subjects with untreated or partially treated episodes of depression are more likely to relapse.

15. Answer: B. According to the DSM-IV, to diagnose major depressive disorder, the subject should have at least five of the nine symptoms of depression over a 2-week period. At least one of the symptoms should be either depressed mood or loss of interest or pleasure in usual activities.

16. Answer: E. According to the DSM-IV, to diagnose a manic episode, the subject should have the symptoms for at least 1 week or for any duration if hospitalization is necessary.

17. Answer: E. According to the DSM-IV, to diagnose a hypomanic episode, the subject should have the symptoms for at least 4 days.

18. Answer: C. According to the DSM-IV, to diagnose a manic episode, the subject should have abnormally and persistently elevated, expansive, or irritable mood lasting for at least 1 week or for any duration if hospitalization is necessary.

19. Answer: A. According to the DSM-IV, to diagnose dysthymic disorder, the subject must have depressed mood for most of the day, for more days than not, as indicated by subjective account or observation by others, for at least 2 years. Of note, in children and adolescents, mood can be irritable, and the duration must be at least 1 year.

20. Answer: B. When subjects with dysthymic disorder have superimposed major depressive disorder, it is often referred as double depression.

21. Answer: C. According to the DSM-IV, to diagnose bipolar II disorder, it is necessary to have one or more major depressive episodes and at least one hypomanic episode. These mood symptoms should not be accounted for by other disorders such as schizoaffective, schizophrenia, etc. Manic episode is a characteristic feature of bipolar I disorder.

22. Answer: D. According to the DSM-IV, to diagnose cyclothymic disorder, there should be no major depressive episode, manic episode, or mixed episode during the first 2 years of the disturbance. After the initial 2 years of cyclothymic disorder, however, there may be superimposed manic or mixed or major depressive episodes.

23. Answer: A. According to the DSM-IV, the criteria for rapid cycling specifier is at least four episodes of mood disturbance in the previous 12 months that meet the criteria for a major depressive, manic, mixed, or hypomanic episode. These episodes are demarcated by partial or full remission for at least 2 months or a switch to an episode of opposite polarity (e.g., major depressive episode to manic episode).