Depressive cognition (Overgeneral memory (Explanations:
OGM as 1) a…
Williams and Broadbent (1986) - Suicide attempters have difficulty retrieving specific auto-biographical memories in response to cue words (e.g. lonely, successful) --> memories more likely to be overgeneral (categoric or extended)
- extended a mood-congruent memory paradigm --> as well as being slower to respond to positive cues than controls also failed to provide specific memory in response to both positive and negative cue words --> response on 1/2 trials with a memory that summarised a category of similar events (I had a teacher who always made me feel successful) compared to controls who were more specific 80% of the time (I felt successful when i completed a charity walk last year)
- Not explained by general deficits in cognitive processing because all p’s performed equally well on test of semantic memory and equal in semantic processing speed
- OGM also found in schizophrenia and PTSD, but not in other anxiety disorders or BPD
- Williams suggested OGM arises because memory search aborted at general level. (they don’t get down to the specific levels) --> linked to depressive difficulty in problem solving (can’t remember specific problems you solved in the past making it harder to solve the current one)
OGM more common when someone has a trauma history such as child abuse, or has intrusive memories they are trying to avoid, e.g. of child abuse, or cancer (Kuyken & Brewin, 1995) = level of OGM might be related to experience of trauma in addition to depression diagnosis
- Replications with nonclinical and clinical samples of depressed, eating disorder, emotional disorder, traffic survivor, cancer diagnosis and PTSD patients.
- Studies of war veterans, traffic accident victims and cancer p's show its not enough to have a history of trauma, you have to have had a prolonged disturbance e.g. these studies included control groups that had been exposed to the trauma but for whom there was no emotional disturbance or PTSD (OGM deficit not found for these groups)
= relationship is moderated by qualitative aspects of the trauma i.e. how severe
- Reactions of trauma might be a function of age --> adult burn victims did not differ from controls in memory specificity, but if burns are sustained in childhood, memory specificity is compromised (Stokes et al. 2004) --> fading affect bias (over time negative events lose their ability to cause negative affect)
Williams (2007) review:
- OGM consistent characteristic of patients with a diagnosis of MDD – 11 studies reviewed show sig. difference between depressed p’s and matched controls
- Occurs in other types of affective disorder e.g. postnatal depression, currently non-depressed patients with previous episodes of major depression/bipolar disorder, and in samples with subclinical levels of depression
- Failures to replicate OGM in currently depressed p's are rare --> not found in study of depressed patients with delusional disorders, patients with psychotic depression, or for patients with seasonal affective disorder
= overwhelming majority show that overgeneral mem is closely associated with depression/depressive symptoms
Why is it important?
- Linked to other aspects of psychological functioning e.g. impaired problem solving (Raes et al. 2005), problems with imagining future events (nonspecificity in specifying future events; Williams et al. 1996), and delayed recovery from episodes of affective disorders (Peeters et al. 2002)
- Memory remains overgeneral in those with history of emotional disorder even if they are not currently in an episode (Mackinger et al. 2000) --> means doesn’t need to be activated by having low mood
- Has predictive value for the course of depression: greater the extent to which people are characterized by reduced specificity for memories, the slower their recovery is (Raes, et al. 2006).
- Even in non-clinical groups or populations that are not suffering from clinically significant pathology, reduced memory specificity predicts increased emotional (depressed) reactivity e.g. to stressful life-events (Bryant et al. 2007)
Limitations of studies used to support:
- Large variation in number of cues used across different studies to support overgeneral memory e.g. study by Moffitt et al. (1994) uses only one cue, and max is 30 by Ramponi et al. (2004)
- Possible that the differences in levels of IQ or memory account for nonspecificity, and not all studies take this into account
- Published studies tend to examine either depression or history of trauma but attribute differences found between clinical and control groups to the variable of interest few studies have examined both
- Trauma often assessed retrospectively
- Not enough longitudinal studies- most use cross-sectional method but cant attribute direct causal relationship
1) recollection of general descriptions less affect than recollection of specific mems --> enables to maintain current goal pursuit.
- OGM as 1) a defensive cognitive style designed to restrict access to painful memories (functional avoidance); 2) a by-product of general demands on mental capacity (reduced executive resources); 3) produced by attention capture/rumination (struggle to do the task because they start ruminating about more general things)
- Consistent with models of PTSD (Brewin, 2001; intrusive mems and flashbacks arise from automatic activation of cues related to trauma = strategies to avoid such mems).
- Correlation evidence: Raes et al. (2006) sig. r between Impact of Event Scale avoidance and AM responses (higher avoidance=higher OGM responses)
2) Studies of young children show that the ability to retrieve and report specific memories in a coherent narrative occurs with the development of supervisory control processes during the age of 3 to 4 years (Fivush & Nelson, 2004),
- Seems unsurprising given that generative retrieval of AM relies on effortful processes, but might not be so clear: when executive capacity controlled for not sig. differences on overgenerality --> Williams and Broadbent (1986)
- Can explain because: generative retrieval requires processing capacity, but also requires inhibition of irrelevant information, and failures of inhibition are most important --> Dalgleish et al. (2007) OG errors r with tasks in which irrelevant material needed to be inhibited (emotional stroop test) and not with tasks that just required sufficient executive capacity overall (explicit memory test of equivalent difficulty)
3) predominance of conceptual self-relevant info in the early stages of memory search may lead to difficulties with the retrieval of specific memories in individuals prone to rumination (repetitive and passive thinking about ones symptoms of depression and the possible causes/consequences of these symptoms- Nolen-Hoeksema, 1991)
- Watkins and Teasdale (2001; 2004) ruminative thinking experimentally manipulated (abstract analytical thinking about causes, meanings and implications and increased self-focused attention), or distraction manipulation (asked p’s to focus on non-self-focused images) depressed patients showed that memory was sig. more specific following distraction than rumination
OGM --> involves training p's systematically to retrieve more specific memories - Memory specificity training (MEST)
- Memory specificity doesn’t typically improve in depressed patients when offered treatment as usual (Raes et al. 2006)
- Broader therapeutic programs e.g. Mindfulness-based cognitive therapy (Williams et al. 2000) or standard cognitive behaviour therapy for depression (McBride et al. 2007) have been found to increase memory specificity
- Serrano et al. (2004)- life review intervention individually administered to 20 older adults with clinically depressive symptoms on a weekly basis for 4 consecutive weeks. Focus = retrieval of specific, exclusively positive memories, with each week focusing on a life period
- Intervention p's showed fewer depressive symptoms, less hopelessness and improved satisfaction two weeks after the last intervention session than controls, and p’s who increased the most in generating specific memories also improved the most
BUT, retrieval of positive episodes/memories = observed benefits due to focus on pleasant events and patients didn’t improve in their retrieval of specific negative memories? = difficult to reliably interpret the effects as a result of improvements in specificity of memory retrieval
- Raes et al. (2008) improve by developing group based intervention for other +ve and -ve materials. P's with current D symptoms and MEST program on weekly basis for 4 consecutive weeks with 10 inpatients.
--> retrieval style sig. more specific following program, not due to reduction in depressive complaints = due to memory specificity alone. P's increased most in SM generation showed most decreases in rumination and experiential avoidance and greater increases in problem solving skills --> remained when changes in DS controlled for
- Limitations: small sample size of only women, no follow up tests included (does risk of relapse change?) and absence of control group = cannot causally attribute improvements to training
Intrusive memories --> imagery rescripting:
- You don’t have to change people memories to make them feel better/make them think more logically, just ensure that images that come into their minds are positive not negative (make it a lot easier to retrieve this positive images then negative images)
- Retrieval competition hypothesis- Brewin (2006) emotions and behaviour are both under the control of multiple memory representations that compete for retrieval. The function of therapy is to create alternative, more positive memories that are more accessible and so retrieved in preference to the dominant negative memories.
- Brewin et al. (2009) 10 p's MDD & intrusive mems given 8 session of IR as a stand-alone treatment.
--> Improvement in depressive symptoms accompanied by a reduction in the frequency, distress, controllability and amount of interference produced by intrusive memories.
-Comparable reductions in rumination over the same period – reflects tendency for intrusive memories and rumination to occur together, and possibly being mutually self-supporting (Pearson et al. 2008) BUT can't rule out that rumination is the key
-About half the sample showed full recovery (typical of depression treatments)
-Better outcome if p's had more sessions and if intrusions were more frequent (i.e. maintaining factor)
- BUT, not always appropriate: depressed p's high in avoidant coping so might not want to explore their intrusive mems --> might need initial period of supportive treatment and build therapeutic relationship before IR is attempted
- Substantial portion of depressed p's who either respond minimally to therapy, respond but continue to have residual symptoms, or relapse within 2 years of recovery –Fava et al. (2007)
- Hollon et al. (2002) only about half of all patients respond to any given intervention, and only about a third eventually meet the criteria for remission
- Most treatments are applied without regard to the specific pattern of depressive symptoms reported by individual patients --> individually tailored treatments may be more effective
- Metacognitive therapy (Wells et al., 2009) teaches p's to switch their attention at will and counteracts unhelpful beliefs.
-Get used to bringing their attentional focus under control. Address positive beliefs about rumination --> why it’s not helpful (don’t feel better after ruminating)
- Mindfulness-based cognitive therapy (Teasdale et al., 2000) teaches p's at risk of relapse to distance themselves from and observe their thoughts without becoming emotionally engaged with them
-Most effective for preventing relapse. Disengagement, not rumination. Can notice thoughts rather than paying attention to them, pay attention to something external instead.
Kuyken & Brewin (1994): high rates of intrusion and avoidance in depressed women inpatients with abuse history (86%). Similar in nature to PTSD and related to severity of abuse.
- Impact of Event Scale (short questionnaire much used in PTSD characterised by intrusive memories). It has two subscales: 1) the extent to which memories intrude, and 2) the extent to which the individual has been trying to exclude the memories from consciousness --> found that scores on this measure were equivalent to those of patients diagnosed with PTSD
- Brewin et al (1996) similar findings- each p reported 2/3 mems with abnormally high levels of intrusion/avoidance for each --> most could be classified as concerning illness and death, relationship and family problems, abuse and assault, and work and financial problems.
- Extent of avoidance/distressing mems may be associated with worse outcome in variety of traumatic situ's (Joseph et al. 1996). BUT, might be the amount of distress associated with these memories rather than amount of intrusion/avoidance that predicts worse outcome
- Brewin et al (1999) the presence of frequent intrusive memories predicts the course of the disorder even when initial symptoms are controlled for = it maintains depression in this subgroup of depressed patients.
- Relationship with OGM? Intrusive memories take up WM capacity, impeding concentration and making it harder to perform concurrent tasks, e.g. retrieving specific AM of past success, that are relevant to recovery
support = reports of poorer retrieval of specific AM among depressed patients with high levels of repetitive memories of adversity
Are memories caused by depression? Or by difficult like events? Might be a reflection of current circumstances (which are triggering negative memories).
- most past research used depressed p's without traumatic events as controls rather than non depressed p's = current life stresses or depression account
- Brewin et al. (1998) interviewed 65 depressed and 65 nondepressed cancer patients, matched on age, sex, type of cancer, and stage of illness. Depressed group divided into severely depressed (meeting diagnostic criteria for depression) and mildly depressed --> severely depressed p's reported sig. more intrusive memories than the mildly depressed patients and controls.
High degree of similarity in the range of intrusive cognitions experienced by PTSD and D patients - But in PTSD the most prominent cognition is more likely to be a memory of a specific incident and in depression it is more likely to be an evaluative thought (Reynolds & Brewin, 1998)
= behaviour and thoughts that focus one’s attention on one’s depressive symptoms and on the implications of these symptoms
- Nolen-Hoeksema (2000): series of studies showing rumination on symptoms, their causes and consequences predicts course of depression.
- Spasojevic and Alloy (2001): found that rumination mediated the relationship between negative beliefs and depression
- In experimental studies, rumination intensifies dysphoric mood and negative thinking, whilst impairing problem solving (Watkins & Baracaia, 2002)
Could rumination be positive?
- repeated focus on upsetting and emotional events and associated thoughts and feelings produces long-term improvements in mental and physical health, as well as reductions in negative mood or depressive symptoms over shorter time periods (Hunt, 1998).
- focus on problems, internal states and other aspects of self-experience can lead to more effective self-regulation (Carver & Scheier, 1990)
There's adaptive and maladaptive self-focus:
- Teasdale et al. (1999) Experiential self-focus improved subsequent social problem solving relative to conceptual-evaluative self-focus in p's with MDD
- Watkins and Baracaia (2002) found that questions inducing a conceptual-evaluative mode (e.g. ‘‘Why do I have this problem?’’) sig. impaired concurrent social problem solving in recovered depressed patients compared to questions increasing direct awareness of mental experience moment-by-moment (e.g. ‘‘How am I deciding what to do next?’’). --> experiential questions sig. improved problem solving in currently depressed patients compared to the conceptual-evaluative questions and a no-question control condition.
- P's with depression more likely to have had recent threatening life events and difficulties and to have had childhoods characterized by adverse experiences (Brewin et al. 1993)
- depressed state is accompanied by changes in memory functioning --> typically find it relatively easier to recall negative events and stimuli and relatively harder to recall positive ones (Matt et al. 1992)
- Generally diagnosed when a persistent unreactive low mood and/or absence of positive affect are accompanied by range of symptoms e.g. cognitive changes (low self esteem, concentration difficulties), changes in motivation, changes in bodily functioning (sleep, eating, sexual problems)
Beck's original model (1979):
- depression from an activation of negative self-schemas, based on high-level, abstract summaries of prior experience (i.e. semantic knowledge)
- BUT, now think self-knowledge also consists of episodic memories. The depressed have general problems retrieving these and at the same time cannot block out a small number of repetitive intrusions (often report memories about other people too, internalise what others have said about them and take it as true)
--> Efforts to avoid these are tiring and reduce cognitive capacity (=less likely to do +ve things that will make them feel better)