Approximately 25% of schizophrenia patients experience course-related depression. (1-4) Depression in patients with schizophrenia is linked to reduced social and vocational functioning, increased likelihood of psychotic relapse and rehospitalization, and other problems. (2-4) Depression in patients with schizophrenia also has been linked to undesirable life events, especially "exit events" such as losing people in their lives, as well as suicidal ideation, suicide attempts, and completed suicides. Overall, it has been noted that approximately 10% of patients with schizophrenia commit suicide. (5) Depressed schizophrenia patients are at particularly high risk for suicide the first few months after diagnosis and after hospital discharge.
Confirm the diagnosis
The best approach to treating depressive symptoms in schizophrenia patients is to formulate a thorough differential diagnosis (Table 1, page 36).
Differential diagnosis of 'depression' in schizophrenia
Acute disappointment reactions
Chronic disappointment reactions
Prodrome of psychotic relapse
Organic etiologies such as medical illnesses--including anemia, cancer, endocrinopathies, infections, and autoimmune, metabolic, cardiovascular, and neurologic disorders--may contribute to a patient's depressive symptoms. "Depression" also can be a side effect of medications used to treat medical conditions, such as antihypertensive and antineoplastic agents, steroidal and nonsteroidal anti-inflammatory agents, and sedative hypnotics, or could be secondary to dose reduction or discontinuation of other agents, such as corticosteroids or psychostimulants. Substance abuse also can play a role in depressive symptoms, either through acute or chronic use or discontinuation. In particular, chronic cannabis abuse can lead to an anergic state that resembles depression, and cocaine withdrawal typically features depression-like symptoms. Additionally, withdrawal from caffeine or nicotine--substances patients with schizophrenia often use heavily--can lead to dysphoric states that are difficult to distinguish from depression.
Antipsychotic-induced dysphoria. Blockade of dopamine receptors is an important feature of all antipsychotics; however, dopamine neurotransmission also is involved in the brain's "pleasure" pathways. Individuals who take antipsychotics may experience reduced joy from once-pleasurable activities. Results of studies on the link between depression and antipsychotics have been mixed. (2), (4) Although some researchers have found depressed mood common among patients receiving antipsychotics, others have failed to show differences between patients treated with antipsychotics and those randomized to placebo.
Akinesia, a parkinsonian side effect of anti-psychotics, can be blatant or subtle. The blatant form involves large muscle groups; these patients present with diminished arm swing, stooped posture, and parkinsonian gait. Easily spotted, such patients are unlikely to be considered depressed.
The more subtle form of akinesia is easier to confuse with depression. It can affect small muscle groups, such as in the face or vocal cords. Lack of responsiveness of facial expression is easily confused with blunted affect, low mood, lack of interest, or emotional unresponsiveness. Subtle akinesia also can impair a patient's ability to initiate or sustain motor behavior. Many activities, from striking up a conversation to changing television channels, involve initiating and sustaining motor behavior, which these patients' basal ganglia are underequipped to do Life becomes boring and patients criticize themselves for "being lazy" Patients with akinesia also are prone to dysphoria. (6), (7) When the lack of spontaneous motor behavior found in subtle akinesia is combined with diminished experience of pleasure due to antipsychotic blockade of dopamine, a patient may feel that "nothing is worth the effort. …