خلق و خوی افسرده در افراد مبتلا به اسکیزوفرنی: مقایسه اقدامات گذشته نگر و در زمان واقعی

Depressed mood is prevalent among individuals with schizophrenia, leading to difficulties in functioning. Typically, depressed mood is evaluated using retrospective assessments during which individuals are asked to recall their mood during the past week or month. However, as individuals with schizophrenia may display memory difficulties, the results of such assessments may be biased, potentially leading to inaccurate clinical characterizations and/or suboptimal treatment. Our aim was to assess the potential impact of long-term memory on depressed mood in individuals with schizophrenia. Employing an Experience Sampling Method (ESM) approach, 51 individuals with schizophrenia and 22 healthy controls rated their momentary emotions up to 10 times/day over a two-day period, along with retrospective measures of depressed mood, long-term memory, quality of life, social functioning, and symptoms. ESM assessment of real-time depressed mood demonstrated discriminant and convergent validity. Among the schizophrenia group, there was a significant correlation between the real-time and retrospective measures of depressed mood. However, once variance due to long-term memory was controlled, the relationship between the real-time and retrospective measure was no longer significant. The findings suggest that a real-time measure of depressed mood may allow overcoming some of the limitations associated with long-term memory difficulties common among individuals with schizophrenia.

Schizophrenia is a chronic illness that brings significant and long-lasting health, social, and financial burdens (Knapp et al., 2004). Further adding to this cost, is the high rate of psychiatric comorbidity common to this disorder (Buckley et al., 2009). In particular, depressive illnesses have been found in up to 75% of individuals with schizophrenia, and are associated with greater disability, recurrence of illness, demoralization, as well as an increased risk of suicide (Baynes et al., 2000). Likewise, sub-syndromal depressive symptoms are present in over 80% of individuals with schizophrenia, contributing significantly to functional difficulties (Zisook et al., 2006).

The samples demographic and clinical information are presented in Table 1. The individuals with schizophrenia were significantly older than the healthy controls. No other significant differences were found. One participant with schizophrenia was excluded from data analysis due to insufficient number of ESM responses. Out of the 20 ESM samples elicited over the two-day period, the participants from the schizophrenia and healthy control groups provided on average 14.85 (S.D.=4.17, range=6–20) and 17.73 (S.D.=2.09, range=14–20). Based on published norms, the individuals with schizophrenia displayed significant long-term memory impairments, with 55% of participants having age-normed standard scores that are at least one standard deviation below the mean and 30% with scores that were two standard deviations below the mean. Only 18% had long-term memory scores within normal range. In contrast, 96% of healthy controls had long-term memory scores within normal range. Findings indicated that long-term memory scores were significantly lower for individuals with schizophrenia compared to the healthy controls (U=65.50, z=−3.47, p<0.001