help me understand the processes of a hoarder, i understand it could be OCD or a person who grew up in poverty with very little, so they take what they can when it is available. what is the current understanding academically and clinically and has it changed in the last 20 years?
The field's understanding has changed fundamentally in the last 20 years, and the central change directly bears on your first hypothesis: hoarding was reclassified from a symptom of other conditions into a standalone diagnosis.
The reclassification (the major change). Under DSM-IV (1994), hoarding was not an independent disorder. It appeared only as one diagnostic criterion for Obsessive-Compulsive Personality Disorder and was clinically treated as a subtype or symptom of OCD. DSM-5 (2013) established Hoarding Disorder (HD) as a distinct diagnosis, placed in the new "Obsessive-Compulsive and Related Disorders" chapter; ICD-11 (effective 2022) did likewise. Twenty years ago the field was actively debating whether hoarding was an OCD variant; that debate is now largely settled in favor of independence. The reclassification was driven by three lines of evidence: hoarding responds poorly to standard OCD treatments (SSRIs and OCD-specific exposure therapy), shows a distinct neurobiological signature, and frequently occurs with no other OCD symptoms.
On your OCD intuition. It reflects the pre-2013 consensus and is partially correct but mostly superseded. Hoarding retains a family resemblance to OCD (hence the shared chapter) and the two can co-occur, but co-occurrence is found in only a minority of hoarding cases (commonly estimated near 15–20%). The phenomenology differs critically: in OCD, intrusive thoughts are ego-dystonic (unwanted, distressing) and compulsions reduce anxiety; in hoarding, acquiring and saving are typically ego-syntonic, and distress arises from discarding rather than from the keeping itself. Hoarding is therefore best understood as related to, but not a form of, OCD.
On your poverty/scarcity intuition. This is largely unsupported as a primary cause. Hoarding occurs across all socioeconomic strata, and childhood material deprivation is not a robust predictor. The "grew up with little, so grabs what is available" account is folk psychology; the clinical model is cognitive and emotional, not economic or rational-scarcity-based. There is a literature associating hoarding with adverse or stressful life events, but a causal role for poverty specifically is weak.
The dominant model — the cognitive-behavioral account (Frost & Hartl, 1996; extended by Frost, Steketee, and Tolin). This is the "processes" you asked about. Hoarding is conceptualized as the product of four interacting deficits:
Neurobiology. fMRI work (Tolin, Saxena, and colleagues) shows that, when deciding whether to discard their own possessions, individuals with HD show abnormal activity in the anterior cingulate cortex and insula — regions involved in salience and emotional/decision-related processing — with a pattern distinct from that seen in OCD. This is interpreted as abnormal assignment of emotional salience to the discard decision. The finding is correlational; whether it is cause or consequence remains unresolved.
Established epidemiological and clinical features. Prevalence is roughly 2–6% (often cited near 2.5%), rising with age. Onset is typically in adolescence (around ages 11–15), with a chronic, progressive course that usually becomes clinically significant in the 30s–40s; help-seeking tends to occur later. Insight is often poor (DSM-5 includes a "with poor/absent insight" specifier). Comorbid depression is very common (~50%), as are anxiety and attention problems. Twin studies indicate substantial heritability (estimates near 50%), and the condition frequently runs in families. Animal hoarding is recognized as a distinct variant, often linked to attachment pathology and, in late-onset cases, sometimes to dementia.
Treatment. HD-specific CBT (Steketee & Frost protocol) is the evidence-based standard, combining motivational interviewing, skills training in categorization and decision-making, cognitive restructuring, and graded practice in sorting, discarding, and resisting acquisition. Peer-facilitated group programs ("Buried in Treasures") show benefit. Outcomes are moderate, not curative; a substantial proportion of patients remain symptomatic. Pharmacotherapy is less effective than in OCD; some weak evidence supports SNRIs (e.g., venlafaxine) and stimulants.
Contested or unsettled. The disorder's precise boundary with OCD and its proper placement within the obsessive-compulsive spectrum remain debated, with some arguing for stronger links to impulse-control or attachment pathology. The causal role of trauma and life events is disputed. The neuroimaging findings lack established directionality. Treatment efficacy is only moderate, with no consensus on the optimal protocol, and subtyping (notably with versus without excessive acquisition) is still being worked out.